On the (dis)unity of the sciences

universeby Massimo Pigliucci

As a practicing scientist I have always assumed that there is one thing, one type of activity, we call science. More importantly, though I am a biologist, I automatically accepted the physicists’ idea that — in principle at the least — everything boils down to physics, that it makes perfect sense to go after a “theory of everything.”

Then I read John Dupré’s The Disorder of Things: Metaphysical Foundations of the Disunity of Science [1], and that got me to pause and think (which, of course, is the hallmark of a good book, regardless if one rejects that book’s conclusions).

I found John’s book compelling not just because of his refreshing, and admittedly consciously iconoclastic tone, but also because a great deal of it is devoted to subject matters, like population genetics, that I actually know a lot about, and am therefore in a good position to judge whether the philosopher got it right (mostly, he did).

Dupré’s strategy in The Disorder of Things is to attack the idea of reductionism by showing how it doesn’t work in biology. The author rejects both the notion of a unified scientific method (a position that is nowadays pretty standard among philosophers of science), and goes on to advocate a pluralistic view of the sciences, which he claims reflects both what the sciences themselves are finding about the world (with a multiplication of increasingly disconnected disciplines and the production of new explanatory principles that are stubbornly irreducible to each other), as well as a more sensible metaphysics (there aren’t any “joints” at which the sciences “cut nature,” so that there are a number of perfectly equivalent ways of thinking about the universe and its furnishings).

But this essay isn’t primarily about John’s book. Rather, it took form while I re-read Jerry Fodor’s classic paper, “Special sciences (or: the disunity of science as a working hypothesis)” [2], together with Nancy Cartwright’s influential book, How the Laws of Physics Lie [3] — both of which came out before The Disorder of Things and clearly influenced it. Let me explain, beginning with Fodor, and moving then to Cartwright.

Fodor’s target was, essentially, the logical positivist idea (still exceedingly common among scientists, despite the philosophical demise of logical positivism a number of decades ago) that the natural sciences form a hierarchy of fields and theories that are (potentially) reducible to each next level, forming a chain of reduction that ends up with fundamental physics at the bottom. So, for instance, sociology should be reducible to psychology, which in turn collapses into biology, the latter into chemistry, and then we are almost there.

But what does “reducing” mean, anyway? [4] At the least two things (though Fodor makes further technical distinctions, you’ll have to check his original article): let’s call them ontological and theoretical.

Ontologically speaking, most people would agree that all things in the universe are made of the same substance (the exception, of course, are substance dualists), be it quarks, strings, branes or even mathematical relations [5]; moreover, complex things are made of simpler things. For instance, populations of organisms are nothing but collections of individuals, while atoms are groups of particles, etc. Fodor does not object to this sort of reductionism, and neither do I.

Theoretical reduction, however, is a different beast altogether, because scientific theories are not “out there in the world,” so to speak, they are creations of the human mind. This means that theoretical reduction, contra popular assumption, does most definitely not logically follow from ontological reduction. Theoretical reduction was, of course, the holy grail (never achieved) of logical positivism: it is the ability to reduce all scientific laws to lower level ones, eventually reaching a true “theory of everything,” formulated in the language of physics. Fodor thinks that this too won’t fly, and the more I think about it, the more I’m inclined to agree.

Now, typically when one questions theory reduction in science one is faced with both incredulous stares and a quick counter-example: but look at chemistry! It has successfully been reduced to physics! Indeed, there basically is no distinction between chemistry and physics! Turns out that there are two problems with this move: first, the example itself is questionable; second, even if true, it is arguably more an exception than the rule.

As Michael Weisberg  and collaborators write in the Stanford Encyclopedia of Philosophy entry on the Philosophy of Chemistry [6]: “many philosophers assume that chemistry has already been reduced to physics. In the past, this assumption was so pervasive that it was common to read about “physico/chemical” laws and explanations, as if the reduction of chemistry to physics was complete. Although most philosophers of chemistry would accept that there is no conflict between the sciences of chemistry and physics, most philosophers of chemistry think that a stronger conception of unity is mistaken. Most believe that chemistry has not been reduced to physics nor is it likely to be.” You will need to check the literature cited by Weisberg and colleagues if you are curious about the specifics, but for my purposes here it suffices to note that the alleged reduction has been questioned by “most” philosophers of chemistry, which ought to cast at least some doubt on even this oft-trumpeted example of theoretical reduction. (Oh, and closer to my academic home field, Mendelian genetics has not been reduced to molecular genetics, in case you were wondering [7].)

The second problem, however, is even worse. Here is how Fodor puts it, right at the beginning of his ’74 paper:

“A typical thesis of positivistic philosophy of science is that all true theories in the special sciences [i.e., everything but fundamental physics, including non-fundamental physics] should reduce to physical theories in the long run. This is intended to be an empirical thesis, and part of the evidence which supports it is provided by such scientific successes as the molecular theory of heat and the physical explanation of the chemical bond. But the philosophical popularity of the reductivist program cannot be explained by reference to these achievements alone. The development of science has witnessed the proliferation of specialized disciplines at least as often as it has witnessed their reduction to physics, so the wide spread enthusiasm for reduction can hardly be a mere induction over its past successes.”

I would go further than Fodor here, echoing Dupré above: the history of science has produced many more divergences at the theoretical level — via the proliferation of new theories within individual “special” sciences — than it has produced successful cases of reduction. If anything, the induction goes the other way around!

Indeed, even some scientists seems inclined toward at least some bit of skepticism concerning the notion that “fundamental” physics is so, well, fundamental. (It is, of course, in the trivial ontological sense discussed above: everything is made of quarks, or strings, or branes, or whatever.) Remember the famous debate about the construction of the Superconducting Super Collider, back in the ‘90s? [8] This was the proposed antecedent of the Large Hadron Collider that recently led to the discovery of the Higgs boson, and the project was eventually nixed by the US Congress because it was too expensive. Nobel physicist Steven Weinberg testified in front of Congress on behalf of the project, but what is less known is that some physicists testified against the SSC, and that their argument was based on the increasing irrelevance of fundamental physics to the rest of physics — let alone to biology or the social sciences.

Hard to believe? Here is how solid state physicist Philip W. Anderson put it already in 1972 [9], foreshadowing the arguments he later used against Weinberg at the time of the SSC hearings: “the more the elementary particle physicists tell us about the nature of the fundamental laws, the less relevance they seem to have to the very real problems of the rest of science.” So much for a fundamental theory of everything.

Back to Fodor and why he is skeptical of theory reduction, again from his ’74 paper:

“If it turns out that the functional decomposition of the nervous system corresponds to its neurological (anatomical, biochemical, physical) decomposition, then there are only epistemological reasons for studying the former instead of the latter [meaning that psychology couldn’t be done by way of physics only for practical reasons, it would be too unwieldy]. But suppose there is no such correspondence? Suppose the functional organization of the nervous system cross cuts its neurological organization (so that quite different neurological structures can subserve identical psychological functions across times or across organisms). Then the existence of psychology depends not on the fact that neurons are so sadly small, but rather on the fact that neurology does not posit the natural kinds that psychology requires.” [10]

Just before this passage in the same paper, Fodor argues a related, even more interesting point:

“If only physical particles weren’t so small (if only brains were on the outside, where one can get a look at them), then we would do physics instead of paleontology (neurology instead of psychology; psychology instead of economics; and so on down). [But] even if brains were out where they can be looked at, as things now stand, we wouldn’t know what to look for: we lack the appropriate theoretical apparatus for the psychological taxonomy of neurological events.”

The idea, I take it, is that when physicists like Weinberg (for instance) tell me (as he actually did, during Sean Carroll’s naturalism workshop [11]) that “in principle” all knowledge of the world is reducible to physics, one is perfectly within one’s rights to ask (as I did of Weinberg) what principle, exactly, is he referring to. Fodor contends that if one were to call up the epistemic bluff the physicists would have no idea of where to even begin to provide a reduction of sociology, economics, psychology, biology, etc. to fundamental physics. There is, it seems, no known “principle” that would guide anyone in pursuing such a quest — a far more fundamental issue from the one imposed by merely practical limits of time and calculation. To provide an analogy, if I told you that I could, given the proper amount of time and energy, list all the digits of the largest known prime number, but then decline to actually do so because, you know, the darn thing’s got 12,978,189 digits, you couldn’t have any principled objection to my statement. But if instead I told you that I can prove to you that there is an infinity of prime numbers, you would be perfectly within your rights to ask me at the least the outline of such proof (which exists, by the way), and you should certainly not be content with any vague gesturing on my part to the effect that I don’t see any reason “in principle” why there should be a limit to the set of prime numbers.

Fine, but does anyone have any positive reasons to take seriously the notion of the impossibility of ultimate theory reduction, and therefore of the fundamental disunity of science (in theoretical, not ontological, terms)? Nancy Cartwright does (and so does Ian Hacking, as exemplified in his Representing and Intervening [12]). Cartwright has put forth a view that in philosophy of science is known as theory anti-realism [13], which implies a denial of the standard idea — almost universal among scientists, and somewhat popular among philosophers — that laws of nature are (approximately) true generalized descriptions of the behavior of things, especially particles (or fields, doesn’t matter). Rather, Cartwright suggests that theories are statements about how things (or particles, or fields) would behave according to idealized models of reality.

What’s the big deal? That our idealized models of reality are not true, and therefore that — strictly speaking — laws of nature are false. Of course the whole idea of laws of nature (especially with their initially literal implication of the existence of a law giver) has been controversial since it was championed by Descartes and opposed by Hobbes and Galileo [14], but Cartwright’s rather radical suggestion deserves a bit of a hearing, even though one may eventually decide against it (I admit to being a sympathetic agnostic in this regard).

Cartwright distinguishes between two ways of thinking about laws: “fundamental” laws are those postulated by the realists, and they are meant to describe the true, deep structure of the universe. “Phenomenological” laws, by contrast, are useful for making empirical predictions, and they work well enough for that purpose, but strictly speaking they are false.

Now, there are a number of instances in which even physicists would agree with Cartwright. Take the laws of Newtonian mechanics: they do work well enough for empirical predictions (within a certain domain of application), but we know that they are false if they are understood as being truly universal (precisely because they have a limited domain of application). According to Cartwright, all laws and scientific generalizations, in physics as well as in the “special” sciences are just like that, phenomenological.

Funny thing is that some physicists — for example Lee Smolin [15] — seem to provide support for Cartwright’s contention, to a point. In his delightful The Trouble with Physics Smolin speculates (yes, it’s pretty much a speculation, at the moment) that there are empirically intriguing reasons to suspect that Special Relativity “breaks down” at very high energies [16], which means that it wouldn’t be a law of nature in the “fundamental” sense, only in the “phenomenological” one. (Smolin also suggests that General Relativity may break down at very large cosmological scales [16].)

But of course there are easier examples: as I mentioned above, nobody has any clue about how to even begin to reduce the theory of natural selection, or economic theories, for instance, to anything below the levels of biology and economics respectively, let alone fundamental physics.

If Cartwright is correct, then, science is fundamentally disunified, and its very goal should shift from seeking a theory of everything to putting together the best patchwork of local, phenomenological theories and laws, each one of which, of course, would be characterized by its proper domain of application.

Here is how Cartwright herself puts it, concerning physics in particular: “Neither quantum nor classical theories are sufficient on their own for providing accurate descriptions of the phenomena in their domain. Some situations require quantum descriptions, some classical and some a mix of both.” And the same goes, a fortiori, for the full ensemble of scientific theories, including all those coming out of the special sciences.

So, are Dupré, Fodor, Hacking and Cartwright, among others, right? I don’t know, but it behooves anyone who is seriously interested in the nature of science to take their ideas seriously, without dismissing them out of hand. We have already agreed that it is impossible to achieve reduction from a pragmatic epistemic perspective, and we have seen that there are good reasons to at the least entertain the idea that disunity is fundamental, not just epistemic. True, we have also agreed to the notion of ontological reduction, but I have argued above that there is no logically necessary connection between ontological and theoretical reduction, and it is therefore a highly questionable leap of (epistemic) faith to simply assume that because the world is made of one type of stuff therefore there must be one fundamentally irreducible way of describing and understanding it. Indeed, ironically it is the anti-realists who claim the mantle of empiricism to buttress their arguments: the available evidence goes against the idea of ultimate theory reduction (it can’t be done in most cases, and the number of theories to reduce is increasing faster than the number of successful reductions achieved so far), so it is a metaphysically inflationary (i.e., unnecessary and undesirable) move to assume that somehow such evidence is deeply misleading. And most physicists wouldn’t be caught dead admitting that they are engaging in metaphysics…

_____

Massimo Pigliucci is a biologist and philosopher at the City University of New York. His main interests are in the philosophy of science and pseudoscience. He is the editor-in-chief of Scientia Salon, and his latest book (co-edited with Maarten Boudry) is Philosophy of Pseudoscience: Reconsidering the Demarcation Problem (Chicago Press).

[1] The Disorder of Things: Metaphysical Foundations of the Disunity of Science, by J. Dupré, 1993.

[2] Special sciences (or: the disunity of science as a working hypothesis), by J. Fodor, Synthese, 1974.

[3] How the Laws of Physics Lie, by N. Cartwright, 1983.

[4] Scientific Reduction, by R. van Riel, Stanford Encyclopedia of Philosophy, 2014.

[5] Rationally Speaking podcast #69: James Layman on metaphysics; Rationally Speaking podcast #101: Max Tegmark on the mathematical universe hypothesis.

[6] Philosophy of Chemistry, by M. Weisberg et al., Stanford Encyclopedia of Philosophy, 2011.

[7] On the debate about the reduction of Mendelian to molecular genetics, see: Molecular Genetics, by K. Waters, Stanford Encyclopedia of Philosophy, 2007.

[8] Superconducting Super Collider, Wiki entry.

[9] More Is Different, by P. W. Anderson, Science, 177:393-396, 1972.

[10] A “natural kind” in philosophy is a grouping of things that is not artificial, that cuts nature at its joints, as it were. A typical example is a chemical element, like gold. See: Natural Kinds, by A. Bird, 2008, Stanford Encyclopedia of Philosophy. Notice that Fodor here is in tension with Dupré, since the latter denies the existence of natural kinds altogether.

[11] Moving Naturalism Forward, an interdisciplinary workshop, 25-29 October 2012.

[12] Representing and Intervening: Introductory Topics in the Philosophy of Natural Science, by I. Hacking, 1983.

[13] Which she couples with “entity” realism, the idea that unobservable entities like genes and electrons are (likely) real. This position is therefore distinct, and in between, the classical opposites of scientific realism (about both theories and entities) and scientific anti-realism (about both theories and entities). See: Scientific Realism, by A. Chakravartty, Stanford Encyclopedia of Philosophy, 2011, and Constructive Empiricism, by B. Monton and C. Mohler, Stanford Encyclopedia of Philosophy, 2012.

[14] Are there natural laws?, by M. Pigliucci, Rationally Speaking, 3 October 2013.

[15] The Trouble with Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next, by L. Smolin, 2006.

[16] For Special Relativity, see chapter 13 of Smolin’s book. This has to do with the so-called GZK prediction, which represents a test of the theory at a point approaching Planck scale, where quantum mechanical effects begin to be felt. Regarding General Relativity, the comment is found in chapter 1.

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127 thoughts on “On the (dis)unity of the sciences

  1. Hi Massimo,

    Correct, but I’m not sure why this would be in contradiction with my statement that the positivists sought a unification of the sciences.

    There is a big difference between seeking to unify science at the level of observational language and seeking to unify science at a theoretical level.

    The Logical Positivists sought to do the first but not the second, not even as a goal. To have that as a goal would have been to make the sort of metaphysical statement that they rejected.

    They would have had no particular quarrel with Dupré, Fodor, Hacking and Cartwright, so I deny that Fodor’s target was a logical positivist idea.

    While I expected you to reject ontological monism, I’m not sure why this follows.

    I reject dualism and neutral monism too. I pretty much reject ontological anything.

    As to why my statement follows, that is a bit too far off topic and more than I have time for at the moment.

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  2. It seems to me that we need to sort out just what physicists mean by “reductionism” if we are to avoid the “straw man” charge. It appears to me that there is more than one thing that physicists mean by the word. I will take the two essays mentioned by Coel:

    Sean Carroll: ‘A sensible reductionist perspective would be something like “objects are completely defined by the states of their components.”’

    Steve Weinberg: ‘Freeman Dyson described reductionism in physics as the effort “to reduce the world of physical phenomena to a finite set of fundamental equations.” I might quibble over whether it is equations or principles that are being sought, but it seems to me that in this description Dyson has caught the essence of reductionism pretty well.’

    So Weinberg’s position could be stated “Reductionism is the effort to reduce the world of physical phenomena to a finite set of fundamental principles”.

    Immediately we can see that these are two very different statements.

    Let’s take an example, a physical instantiation of a Turing Machine implementing a ‘Eratosthanes Sieve’ algorithm. Using Weinberg’s definition I could say that the fundamental principles that this reduces to are computation and the mathematical nature of prime numbers.
    Using Carroll’s definition this object is completely defined by the state of its components. Its components might be silicon gates, or rods and cogs or balsa wood and the states of those things define how the algorithm is instantiated in this particular case, but do not completely define the object.

    And the deeper down you get into the states of the components – molecules, atoms, quarks, quantum fields etc, the farther away you get from what defines the object. The mathematical nature of computation and prime numbers are not things that can reasonably be called ‘components’ of this object.

    Weinberg’s definition seems uncontroversial as he says nothing about this finite set of principles belonging to just one discipline, but it also seems at odds with the claim reported by Massimo above.

    Carroll’s “reductionism” seems to me to be self evidently wrong or at least having no utility.

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  3. I fear I may regret entering this conversation, given how fruitless discussions of this topic have been in the past, but here are a few remarks.

    Robin Herbert: “I deny that Fodor’s target was a logical positivist idea.”

    Jerry Fodor (the first sentence of “Special Sciences”): “A typical thesis of positivistic philosophy of science is that all true theories in the special sciences should reduce to physical theories in the long run.”

    Given that reductionism was defined by Ernest Nagel, in his “Structure of Science”–and given that Nagel was one of the central figures of the Logical Positivist movement–Fodor is clearly correct.

    —————————————–

    As for reductionism and its merits/demerits, I’m glad to see that we are all on the demerit side of epistemological reductionism — though I seriously question the sincerity of some who have jumped onto this wagon, here, given previous discussions of the topic — ontological reductionism is similarly hopeless, unless one is speaking strictly of the (relatively weak and uninteresting) token physicalist variety.

    In order for ontological reductionism to be true, it would have to be the case not simply that every concrete individual in the world is a physical object, but that every class, type, and kind is a class, type and kind belonging to a physical science. (Presumably, no one in this discussion is a nominalist, so the fact that classes, types, and kinds exist should not be controversial.)

    Included in Fodor’s argument against the reduction of theories — and thus, of laws and explanations — is an argument against the reduction of types, classes, and kinds. Hence his point re: monetary exchanges, being realizable in indefinitely many physical substance types, the conjunction of which is not a class in physics — or any other physical science. (Yes, I am aware that Coel has argued elsewhere that such classes are in fact psychological and therefore, ultimately, neurochemical, but I am limiting my discussion here to serious proposals.)

    The disunity of science is something that Western thinkers have known since antiquity and is one of those things that we seem to have un-learned in the modern era. (Massimo and I actually had quite an interesting discussion of the essentially modern roots of “explanatory/ontological monism” in our BHTV conversation on scientism.) Aristotle understood it–hence his remarks regarding the differing types of “rigor” demanded by the different sciences; Montaigne understood it — see his “Apology for Raymond Sabond.” It’s when you get to Descartes that the fantasies about “one world and one theory” start.

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  4. Richard, yeah, it’s not just a slight exaggeration, it’s a pretty serious misrepresentation of the situation. A recent survey of a number of opinions of philosophers, co-authored by David Chlamers, clearly pointed to realism having won the day, especially within the epistemically relevant community, philosophers of science.

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  5. Aravis, well put (except for the part about question people’s sincerity, I prefer to think that we all don’t necessarily think everything through for sufficiently long). I was tempted to bring in Fodor’s distinction btw tokens and types, and now I regret now having done it, but it was difficult in first draft to find a sufficiently clear way to put the issue.

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  6. Reblogged this on no sign of it and commented:
    I’ve found both the article and its comments particularly invigorating, and also learned much from the supporting material in the footnotes.
    I suppose some would say that admitting to a disunity of the sciences would threaten the enterprise of scientific theories and their research as a whole; but I see it quite differently. The diversity of the sciences should motivate concentration in research in the individual areas of science (liberated from demands for ‘unification’ conformity), while those searching for a ToE should be spurred on to more complete – and more demonstrable – theories than we have today.

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  7. > According to Cartwright, all laws and scientific generalizations, in physics as well as in the “special” sciences are just like that, phenomenological.

    I haven’t read Cartwright, but this sounds very, very meaningless. Ohm’s law and QED are both phenomenological, “just like that”. But with QED one can calculate physical properties with an astonishing degree of accuracy, up to 10 significant figures. Ohm’s law is a rather crude approximation.

    Calling both QED and Ohm’s law “phenomenological”, is like calling both a nuclear sub and a hand axe “weapons”.

    Sometimes philosophy of science looks like a hand axe analysing a delicate Swiss watch.

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  8. Massimo,

    It isn’t a question of it being “disconnected,” but rather of basic principles being insufficient. This could happen in a variety of ways, one of which of course is via strong emergence, but also if it turns out that laws of nature have limited domains of application.

    I may be missing a nuance here, but it is not clear to me why an additional law in an additional domain could not also be considered “basic”. Is reductionism supposed to reduce to only one solitary law? That is not how I ever understood it. Admittedly, I see the problem if such an irreducible law is found at an extremely highly emergent level. But then again, an irreducible law is like a missing link: using it as evidence has something of a god of the gaps to it.

    But as a thinking and curious being, ar you concerned only with practicalities? Because if so, most of fundamental physics, and, say, all of cosmology, is utterly non-practical…

    I meant to say that I am unconcerned about the reductionist project because it seems clear that it will never work out anyway.

    The discussion is really about how we should think of scientific theories (as approximating truth, or as empirically adequate), and even the very goals of science itself (is it after truth, or after empirical adequacy?).

    Sadly I cannot quite appreciate the difference.

    Unless the anti-realist actually believes that there exists no reality against which to measure the theory for empirical adequacy the difference to “approximating truth” is just one of an irrational dislike of the term truth. Because otherwise, if they did not believe that there was a reality, how would they explain that one theory is indeed more adequate than another? It surely won’t make any difference to scientific practice.

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  9. What Coel’s argument points to is a Curry-Howard*-type correspondence between scientific theories and computer programs. This would provide a unifying aspect of scientific theories. The disunifying aspect occurs when theories are coded in different (domain-specific) programming languages. One could have a language for molecular genetics and a language for particle physics, for example. The issue is not really about reduction and emergence, but about what happens when attempting to translate or compile from one language to another.

    * http://en.wikipedia.org/wiki/Curry-Howard_correspondence (the correspondence between mathematical proofs and computer programs)

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  10. Hi Aravis,

    Given that reductionism was defined by Ernest Nagel, in his “Structure of Science”–and given that Nagel was one of the central figures of the Logical Positivist movement–Fodor is clearly correct.

    “The Structure of Science” was published in the 1960’s when Logical Positivism was well.past it’s prime if not entirely defunct. Their project to unify science had foundered during the Second World War.

    The term “Logical Positivism” was coined by Carnap in 1935, in “Philosophy and Logical Syntax”, to describe the views of the Vienna Circle, views which were already well established by the 1920’s.

    The Circle grew out of the Ernst Mach Society, dating about a decade earlier with a philosophy based on ideas published by Ernst Mach in the late 19th century.

    So the type of reductionism defined by Ernst Nagel in 1961 cannot be said to be relevant to Logical Positivism..And, even so, it is not entirely clear that Nagel, in defining reductionism, is necessarily advancing the view that all theories reduce to physical theories – the concept of reductionism does not, by itself, entail that. And it is not clear that Nagel was a Logical Positivist at all. He had no affiliation with the Vienna Circle and Patrick Suppes biography of him says:

    Throughout his career Nagel tried to combine the best elements of Cohen’s philosophical realism and Dewey’s radical instrumentalism

    The essay “Physicalism”, that I referred to earlier by Otto Neurath makes it plain that they are seeking a unity based on an observer language rather than a unity at the theoretical level, and he at least claims to be speaking on.behalf of the other members of the Vienna Circle..

    The idea of unifying science at the level of an observer language is also put forward by Carnap in “The Unity of Science” in 1934

    So, I stand by what I said, when the Logical Positivists spoke of the unity of science they meant, and in fact clearly stated, that science should be unified under a common observer language, not at the level of theories..

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  11. Thank you for the responses, Massimo. My apologies if I appear to be dissing philosophy. But on the one hand you seem to be saying that biology and physics are sufficiently commensurate theories that biology can be seen as compatible with the second law of thermodynamics, while on the other Cartwright says that no ‘fundamental unification’ between them is possible. Would you not agree that there is some tension here? One way ahead might be to invest effort in working out how these two statements might be made consistent. My comment should be taken as saying that I’m more inclined to look for flaws in Cartwright’s reasoning. These would both be philosophical investigations, I think.

    I worry that there are tensions elsewhere, too. For example,

    “Theoretical reduction [as opposed to ontological, which we accept], however, is a different beast altogether, because scientific theories are not “out there in the world,” so to speak, they are creations of the human mind.”

    Quarks, hadrons, nuclei, atoms, molecules, etc, are all theoretical posits. As are the interactions between them. To accept the particles as real, which I take to be the import of ontological reductionism, is to accept the interactions. But this projects the theory ‘out there’ too, despite it being a creation of the mind. In other words, ontological reductionism slides into theory realism, at least for physics.

    “We have already agreed that it is impossible to achieve reduction from a pragmatic epistemic perspective, and we have seen that there are good reasons to at the least entertain the idea that disunity is fundamental, not just epistemic.”

    I take the first clause to mean that, in the case of chemistry and physics, say, we can’t demonstrate that some chemical property is a logical consequence of the underlying physics because we can neither do the required mathematical proof nor wait for the calculations to finish. That’s the epistemic gap—we just don’t know all the consequences of the theory. That’s fine. But what does it mean to say that this ‘disconnect’ is ‘fundamental’, in addition? To me this says that the world really is a patchwork quilt. But again that is to accept theory realism, as I understand it. So I’m rather confused. But many thanks for making me think!

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  12. Alexander, the anti-realist explains empirical adequacy independently of truth on the grounds that theories are empirically adequate because they have been selected for being so. Since theories can be underdetermined by the evidence, a theory can be adequate and yet false. Newtonian mechanics is the obvious example: its picture of space-time is considered wrong nowadays, and yet, if you want to send a rocket to the moon you still use it, and not quantum mechanics.

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  13. Patrick, sometimes concluding hastily that someone has been using a blunt instrument is simply a reflection of the fact that we missed the nuance in the other’s argument. In this case, I don’t see what precision has to do with whether a law is phenomenological or not, since the latter is a question of domain of application. My kitchen scale is very precise, but only in a very narrow range. I can’t use it to weigh an elephant.

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  14. Massimo: “Richard, yeah, it’s not just a slight exaggeration, it’s a pretty serious misrepresentation of the situation. A recent survey of a number of opinions of philosophers, co-authored by David Chlamers, clearly pointed to realism having won the day, especially within the epistemically relevant community, philosophers of science.”

    Massimo, we’ve been talking at cross-purposes. My point is not about what proportion of philosophers label themselves “realists” or “anti-realists”, but about the way those labels are defined and used. I’m suggesting that philosophers are often using these labels in a misguided way, and failing to make a meaningful distinction. The SEP quote indicated that philosophers are having great difficulty saying what they mean by these terms, and the remainder of the article supports that assertion. Elsewhere that SEP article cites a few philosophers who think the question of scientific realism vs anti-realism is a pseudo-question, and I think that’s largely true. There is a meaningful problem to be resolved (or at least confusion to be dissolved) in the vicinity of that question, but the question itself is unhelpful.

    Philosophers often create a term of art that corresponds to some distinction they intuitively feel needs to be made. But sometimes their intuitions are misguided and they are making a false distinction. Consequently they are unable to come up with any univocal and adequate definition of the term. What they are often doing is just buttressing their intuitive feeling of a distinction with misguided language that repeats the original false distinction in another form. Even if they do broadly agree on a definition, it may be a counter-productive one. A more Wittgensteinian appreciation of language would help.

    When we use a familiar ordinary language word, we can be guided by our well-established linguistic competence with that word. We don’t usually need a definition. When we’re dealing with a philosophical term of art we are at the mercy of philosophers to tell us what they mean, and if they can’t tell us clearly enough, we should question whether the term is worth using. More generally, it would help to stop leaning so hard on questionable philosophical terminology, and stick to ordinary language as much as reasonably possible. (I’m not denying that philosophical terms are sometimes useful. I for one like the term “supervene”.)

    BTW I’ve now read Weinberg’s “Reductionism Redux” article, mentioned by Coel, and based on that I think you are misinterpreting him. True, he’s ambiguous. But I think the evidence is predominantly against your interpretation, and renders it uncharitable. (Note: that article was from 1995, and he may have changed his position since. But that seems unlikely.)

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  15. Richard, I am *very* familiar with the realism/anti-realism debate, and I consider it one of the most engaging in modern philosophy of science, with very clearly stated and ably defended positions. I have no idea where the SEP author gets his impression.

    As for Weinberg, I stand by what I wrote. I have not read the ’95 article, but last year that’s what he was thinking.

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  16. Patrick,
    One doesn’t need to be particularly philosophical to recognize the difference between a hand axe and a nuclear weapon. On the other hand, one does in order to sense the continuity and connection. The issue of this discussion is how to extract the big picture from all the details, when the consequence of trying only seems to produce ever more details. Maybe we need to keep the inherent dichotomy in mind and understand both generalizing and specializing are framing devices and when the focus on one loses sight of the other, there is a potential need for course correction. In the army, specialist is one rank above private and generals run things, but in the sciences, specialists are in charge and generalists are dismissed. If I was to offer up a general theory of everything, it would be that time is to temperature what frequency is to amplitude and space is both infinite and absolute/equilibria, but that would step on a lot of toes.

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  17. Hi Massimo,

    The reductionism you criticise is a view you find to be common among scientists. When I say that I fear a straw man, I just mean that this is not apparent to me. You have had more such discussions, but since most of the indefensible definitions of reductionism you refer to come from anti-reductionists (Fodor), and since most of the quotes coming from the likes of Weinberg may be more charitably interpreted, perhaps the problem is not that the physicists have deeply incoherent views but that they have failed to communicate what they mean effectively.

    So, when Weinberg says “all scientific theories reduce to the physical”, you interpret him to mean that there should be bridge laws connecting different scientific theories. However it is not at all clear to me that this is what he means, because he may be ignorant of Fodor’s work. He may only mean that any model built with appropriate low-level laws will exhibit the behaviour described by high-level laws.

    I agree that we see more proliferation than successful reduction. That doesn’t mean that reduction is impossible. Reduction is hard. Proliferation is tremendously useful for the study of phenomena at a high level. Since this is true regardless of whether reductionism is correct I don’t think this empirical fact helps the argument either way.

    (On my analogy to computer programming)
    > But if science isn’t about fundamental understanding I don’t know what it is about.

    If reductionism is correct, the fundamental level of reality is physics (corresponding to ones and zeroes in programming). Biologists don’t care about this fundamental level of description. Biologists care about understanding high level structures, like a high-level programmer. So it is no argument against reductionism that particle physics is irrelevant to biology, because biology is not a branch of science which is concerned with the fundamentals of reality.

    > Then stop making grandiose claims about how it is all about physics.

    It’s all about physics in the same sense that computer programming is all about marshalling ones and zeroes: technically correct but not useful for most analysis which can only profitably done with higher level concepts.

    On the “In principle/What principle” question, can you give an example of a case where that question is appropriate? As I said, to me “In principle, X” just means that “All practical considerations aside, X”, and this statement can be itself considered to be a principle. So, the statement “All practical considerations aside, a decrease of supply or increase in demand should drive up prices”, is equivalent to “In principle, a decrease …”. If you ask the redundant question “What principle”, your redundant answer will be “The principle of supply and demand”. It’s not begging the question, it’s repeating the original statement as you have essentially requested your interlocutor to do.

    What I think you perhaps mean to ask is “How do you justify that proposition?” That’s a much more helpful way to phrase the question and is less likely to leave your interlocutor nonplussed.

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  18. Hi Wm. Burgess,

    Dupre asks Rosenberg `So the strongest thesis you can endorse is that everything supervenes on the physical state of the universe?’ To which Rosenberg answers `I’m comfortable with that’. He basically concedes to the most anti-reductionist position imaginable.

    This encapsulates the whole discussion! What physicists mean by “reductionism” is what philosophers term “supervenience”. (“the lower-level properties of a system determine its higher level properties”). Whereas by “reductionism” philosophers mean much stronger notions, e.g. as espoused by Nagel.

    As Churchill said about America and Britain, we’re “divided by a common language”!

    Thus the physicists get baffled that philosophers attack “reductionism”, because reductionism-as-understood-by-physicists (aka “supervenience”) is pretty innocuous and obviously true (unless you’re a vitalist or dualist, which no-one sensible is). But then the philosophers mistakenly interpret that as defending much stronger philosophical notions such as reductionism-as-defined-by-Nagel.

    Physicists do not hold to these strong notions, since after all, they deal with this stuff in their everyday life, and see that the stronger versions are non-starters, plus they are not idiots and are pretty pragmatic about such things.

    If one is required to `give the states of all the particles making up the environment’ in order to completely explain any particular configuration of atoms, this is the opposite of reductionism.

    It might be the opposite of reductionism-ADBN but it is exactly what reductionism-AUBP entails. Take, oceanography, for example. One can model the oceans in terms of low-level physics and the equations of fluid mechanics. But, if one wanted to model and reproduce, say, El Nino events, one would have to specify all the starting conditions, and all the local contingent factors such as locations of land-masses etc (which, by the way, is exactly that physical oceanographers do). That is all entirely in line with reductionism-AUBP.

    Hi Aravis,

    In order for ontological reductionism to be true, it would have to be the case not simply that every concrete individual in the world is a physical object, but that every class, type, and kind is a class, type and kind belonging to a physical science.

    That, again, is a stronger version of reductionism than any physicist holds to, since it is trivially false. The reductionism-AUBP version is that the higher-level types are composed of — being a pattern of — lower-level physical types.

    Hi David Ottlinger,

    Coel, its very hard to understand your dismissal of this idea when you have defended it so many times yourself.

    What I’ve said on this thread is entirely consistent with everything I’ve said on previous threads. If you don’t think so it is likely because we are “divided by a common language”. In previous threads I’ve also pointed out the differences between physicists’ conceptions of these things and philosophers’ conceptions.

    The stronger versions of reductionism might be notions discussed by philosophers, but they are not promoted within physics (indeed, most physicists would be unaware of them, which is why they get baffled by philosophers arguing against “reductionism”).

    That was my fifth comment, so enjoy yourself everyone while I go off to purdah.

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  19. Coel, no at all. Philosophers mean a number of things by “reduction,” including supervenience (a philosophical term). They make distinctions that most physicists don’t appreciate (it’s not their job anyway). So this sort of discussion typically isn’t the result of physicists and philosophers talking past each other, but of the fact that the philosophers make many more distinctions than the physicists typically (there are exceptions) appreciate or care for.

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  20. @ Coel: “This encapsulates the whole discussion! What physicists mean by “reductionism” is what philosophers term “supervenience”. (“the lower-level properties of a system determine its higher level properties”). Whereas by “reductionism” philosophers mean much stronger notions, e.g. as espoused by Nagel.”

    THANK YOU. That was incredibly enlightening and clarifying for me.

    I don’t think this quite explain it all, however. When Pigliucci argues that the empirical evidence is against reduction since so few phenomena have been reduced vs. lots of new ones have not been, this is simply doing bad science (sorry, Pigliucci) – it’s arguing against a theory by alluding to predictions it doesn’t make, much like arguing against evolution by arguing that there aren’t any missing links. Pigliucci can at least be interpreted as arguing here against the existence of any particular subservience, by raising the (false) premise that the existence of any rules connecting the supervinient and fundamental levels would imply that such rules would be easier to find than special sciences would be. He is, arguably, arguing against supervenience itself (or at least against any specific, regular supervenience).

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  21. Actually I share the worry voiced by several commenters here that the stance of scientists might be misrepresented. From my (admittedly limited) experience with physicists a “theory of everything” would simply comprise the theoretical possibility to describe the universe at a given time by a state vector of fundamental entities (fields, strings, branes, what have you) and further its time development by fixed transition rules (a wave function, system of differential equations, whatever). That’s it. I never heard a physicist voice the opinion that everything that can be observed in the universe on any level of observation would need to be deductible or explainable on this basis (or at least I never understood physicists to say so). Just that everything that is observed in the universe is constrained by these transitions. I think this is what Coel means by “simulation” even though the term does not seem to be wholly appropriate.

    I think it is interesting to contemplate in what respect such a “TOE” still constitutes a “physical theory” or even an “explanation of all physical events”, but that seems to be the main reductionist claim and it while it is bolder than ontological reductionism, it is much more sane than the view attributed to scientists in this essay.

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  22. Coel wrote: “That, again, is a stronger version of reductionism than any physicist holds to”

    ———————————————–

    As I said, you can hold a purely Token Physicalism, but it is not very interesting. It certainly doesn’t get you anything near the Unity of the Sciences thesis.

    But then you say this:

    “The reductionism-AUBP version is that the higher-level types are composed of — being a pattern of — lower-level physical types.”

    This is *not* merely a Token Physicalism and is clearly false. Sea shells, gold nuggets, pieces of paper, and electronic currents may all be instances of “currency,” but its not true that currency is “composed of” a “pattern” of these distinct physical types and notice that the conjunction of these physical types is not itself a physical type.

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  23. Hi Alexander,

    you wrote:
    “Second, whether we can achieve the unity of scientific theories, or the reduction of all to a few fundamental rules, in practice. I understand that it appears arrogant of somebody to say that we should be able to do that in principle even if they currently have no idea where even to start. The thing is, it quite simply follows logically from the previous consideration. If there is unity to the universe, then one should in principle be able to describe it in a unified fashion, although one might need greater capabilities to achieve that aim than humans will ever realistically have at their disposal.”

    I have come across this statement (or something like this) quite often and I actually don’t see how it follows. It could be that there is “unity to the universe” but the only way to represent this unity is by the universe itself. In my experience it is here that scientists might routinely err uncritically.

    A similar mistake seems to occur whenever Coel (or DisargreeableMe) seem to imply that systems that are describable by some mathematical notation can also be simulated. I don’t see how this follows either.

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  24. Panpsychist, Pigliucci wasn’t arguing that at all. He was simply explaining Fodor’s and Cartwright’s arguments. It is fascinating to me that a number of people here have simply assumed that I defend the positions I wrote about, as opposed to merely entertain the possibility because it opens one’s mind…

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  25. Mira, I think we all know and acknowledge what physicists *technically* mean when they talk about a theory of everything. The issue is when they — usually in casual conversations or blog posts, never in serious publications — go on from there to draw unwarranted metaphysical inferences.

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  26. Coel,

    “What I’ve said on this thread is entirely consistent with everything I’ve said on previous threads. If you don’t think so it is likely because we are “divided by a common language”.”

    Yes, in so far as what you say here is inconsistent and you have always been inconsistent. The whole point (or at least an essential part) of supervenience was to argue that explanations are sui generis. Mental events are explained by reference to other mental events, chemical events are explained by other chemical events and so on. Mental events (for instance) are causally grounded in physical events but physical description does not entail (logically) any mental description. (Yes we can correlate mental events to physical states but that is done to explore the causal grounding of mental phenomena not to explain mental events.) So when you insist that to fully explain aesthetics we would have to know everything about the brain, as you did once to Arvis, or that currencies can be explained in physical terms you are being reductionist in the *philosophical* sense. Hence whatever your view is it is not a supervenience view. Generally you swing back and forth by a thorough-going equivocation on causal and logical entailment (dressed up-in this case-in the language of simulation). So once again, there is at least one physicist, Coel Hellier, who is defending reductionism.

    All,
    Yes we do need to define redcutionism/supervenience/emergence. However there is a very concerted effort do so on the part of philosophers. Looking into SEP scientific ant-reductionism page would be the place to start.

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  27. The light at the end of the tunnel:
    Rather than pursuing a theory of everything as you suggest Professor, I would suggest you search for a single truth of everything. Surely you would agree that theories are theoretical at best and truth is absolute. Why mess around? As for a single truth that unites everything, yes there is One, just One, and the effect is unity and freedom at last.
    I’ll leave the light on,
    =

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  28. A few additional thoughts:

    RichardWein The SEP isn’t always everything. As I noted in a comment on Massimo’s “Stoic Egg,” it doesn’t even have an entry for Cynicism. I don’t even comprehend that. Oh, the SEP is helpful at times, but it’s not a be-all and end-all.

    Massimo Per my second comment, and your differentiating between scientists and philosophers, when we get into the dimension of “paradigm shifts,” do most scientists, even leading lights, actually thing much about possible shifts in terms of philosophical issues, or not? If they do, do certain schools of philosophy have some weight?

    And, I was wondering if you would also, speaking of paradigm shifts, connect this to your essay of a few weeks ago about a possible new new synthesis in evolutionary biology. Is anything that you mentioned in this essay, and that we’re now discussing, part of the mix on that? Is biology different from physics as to what specific philosophical issues, justifications, ways of thought, etc., get brought up?

    And, I would have liked to have more about Fodor’s tokens and types, even at the risk (or the delight!) of getting into semantics, semiotics, etc. (Like one of the linguistic-related essays that I thought was going to deliver something like this and didn’t.)

    Coel and others with similar thoughts on computationalism: I see this as part of the problems with the Many Worlds Hypothesis and everything tangentially affiliated with it in cosmology. Sorry. Get me some real-world evidence. I mean, I can run a computer simulation for anything and everything logically possible, and theoretically come up with worlds with silicon-based life, like the Horta of Star Trek fame.

    So, Coel, don’t purdah yourself up yet, whether as a Muslim woman or a British office-seeker on the hustings.

    All: Going beyond the issue of computationalism, this essay may be of interest. It references Smolin, and some of the same thoughts of Smolin as Massimo did:

    Smolin says physicists must abandon the notion of time as an unchanging ideal and embrace an evolutionary concept of natural laws. … (A)t the heart of his book is a worthy idea: Smolin is against the reflexive reification of equations.

    Interestingly, in physics, it notes the shift from positivism to Platonism.
    http://aeon.co/magazine/science/margaret-wertheim-the-limits-of-physics/

    Aravis Thanks for the Montaigne thoughts. On your second comment, I’d argue that Coel is bringing Platonism to money. That’s the simplest explanation, and let’s call a spade a spade.

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  29. Coel explains pretty well why the attack on reductionism is a silly straw man attack.

    Richardwein is also right that the scientific realism vs anti-realism issue is hopelessly confused among philosophers. The issue does arise among physicists, such as in the Bohr-Einstein debates of the 1930s, in interpretations of quantum mechanics today, and in other modern areas like inflation or string theory. But that SEP page on scientific realism reads as if it was written in the 19th century, except that 19th century philosophers were more in touch with actual science.

    I found the study claiming that 75% of philosophers favored scientific realism, but the term was not defined, so this may not mean much. Maybe the survey should have asked, “Is there a consensus on the meaning of scientific realism? Who was the realist, Bohr or Einstein?”

    My guess is that such questions would have made it clear that the terms realism and antirealism have become meaningless to modern philosophers.

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  30. Coel,

    More thoughts on simulation and why it doesn’ get you out of questions of redctionism and anti-reductionism. Take your example of running a full simulation of the Earth. A physical simulation after billions of simulated years might describe a cheetah. (I am imagining a computer program here.) But that would be quite unavailable to the simulators. At best (I believe) they would describe a mass 1.1 to 1.4 m high 65 to 80 cm long weighing 35 to 65 kg moving up to 120 km/h (I assume they use metric). However it would not, allowing that it is a *physical* simulation, describe an animal, a cheetah, a mammal, a predator, anything beautiful, savage or frightening. It would describe the cheetah only in so far as it is a physical thing. Biological, aesthetic, and many other phenomena will be missing from the simulation.That is to say, no part of the simulation would describe the cheetah except as it is a physical body. This is because a complete recreation of the Earth and her history would *causally* entail the existence of cheetahs with all the same biological and aesthetic qualities but a complete physical description does not *logically* entail a cheetah’s biological features, aesthetic features etc. Or so say I. I am an anti-reductionist. The reductionist would have to say that a complete physical description would describe *all* of the cheetah’s features. The reasons for thinking thats impossible (multiple realizability, the irreducibility of the normative and telelogical), have been rehearsed here many times before. Whichever side you land on, I don’t think simulation clarifies much.

    John Dupree and Alex Rosenberg sat down to have a very similar conversation. Sadly they chose Elephants. https://www.youtube.com/watch?v=3cDtS-0ozfg

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  31. DM: I find your defense of reductionism the most puzzling, insofar as you are a computationalist.

    If computationalism is true, then psychological kinds are — by definition, as well as in fact — physically heterogeneous ; that is, they cut *across* physical types. And if *this* is true, then psychological laws are irreducible and psychological explanation is autonomous.

    You have to remember, Fodor used to think more highly of functionalism than he does now. Indeed, “Special Sciences” — as well as Putnam’s “The Nature of Mental States” and “Philosophy and our Mental Life” — were all considered some of the best arguments *for* a functionalist account of the mind, precisely *because* they showed that psychological states/laws/explanations could not be identified with any physical states/laws/explanations.

    Indeed, Fodor, in his essay “Fodor’s Guide to Mental Representation”, describes functionalism as representing an ideal autonomous level at which to pitch psychology:

    “If Functionalism is true, then there is plausibly a level of explanation between commonsense belief/desire psychology, on the one hand, and neurological (hard science) explanation, on the other.” (p. 9, in A Theory of Content and Other Essays).

    Functionalism — and its computationalist sub-species — are incompatible with the reductionist, as we have been describing him, and who is probably best represented by JJC Smart (see his “Sensations and Brain Processes”) or by David Armstrong’s “Central State Materialism.” (see his “A Materialist Theory of the Mind.”

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  32. Hi Massimo,

    thank you for your response. Upon rereading your article I realized that it was me who misunderstood the position you criticized. You were stating that (often/sometimes) scientists defend that a particular observable phenomenon has to be reducible “because it all boils down to physics anyway” (very rough summary). This is a line of argument that I have come across and I agree it is probably confused.

    I actually turned the statement on its head when I paraphrased the position as “all observations are deductible from fundamental laws”. I now understand that these two positions are not at all logically entailed since even if there were a hierarchy of domains with functioning bridge laws, it could still be that they worked only in the “down (towards fundamental)” direction and not in the other.

    It seems some other commenters have confused this as well, so maybe this post contributes to reducing the confusion that I helped to amplify. Cheers!

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  33. “… physicist Philip W. Anderson … against Weinberg … : “the more the elementary particle physicists tell us about the nature of the fundamental laws, the less relevance they seem to have to the very real problems of the ‘rest’ of science.”

    Amen!
    Physics has three expressions:
    Physics 1 (P1): Expression 1 = physical universe {prequark, quark, (baryon, lepton), atoms, … galaxies; DNA… etc.},
    Physics 2 (P2): Expression 2 = bio-‘attributes (not functions)’ {intelligence, consciousness, mortality, spirituality, etc.},
    Physics 3 (P3): Expression 3 = Math {zero, finite numbers, infinities}.

    As the current mainstream particle physics is all about the P1 without any sign of linkages to P2 and P3, Anderson had intuitively sensed that it becomes more and more irrelevant to the fundamental laws. Amen, again.

    “Cartwright distinguishes … : “fundamental” laws are those postulated by the realists, and they are meant to describe the true, deep structure of the universe. “Phenomenological” laws, …, and they work well enough for that purpose, but strictly speaking they are false.”

    Amen!
    The Standard Model is 100% phenomenological with zero (absolutely zero) theoretical content as there are many free parameters which must be put in by hand and no theoretical base (or language) to describe the SM fermions (baryons and leptons). Thus, the two tasks below became the ‘central’ issues for physics in the past 50 years as the SM is phenomenologically ‘complete’ in the early 1970s.

    One, deriving those free parameters (the Cabibbo and Weinberg angles, Alpha, mass-charges, etc.),

    Two, deriving the string-unification, describing the SM fermions with a theoretical ‘language’.

    Yet, up to this moment (40 some years after 1970s), both tasks are failed totally and dismally by the ‘mainstream’ physics (composed of tens-thousands of top physicists). Thus, the conclusion is very simple, “The hardest thing of all is to find a black cat in a dark room. Yet, there is no chance to find one if there is no cat.” It means that those SM free parameters are simply ‘happenstances’, without any theoretical base; and this is the ‘base’ for multiverse which encompasses all possible ‘parameters. Without any chance to resolve the two tasks about, the multiverse is the only ‘rescue’ for the mainstream physics.

    Thus far, the dissenters (such as Paul Steinhardt, Peter Woit) of this multiverse is only a very tiny minority in the physics community, and their only objection is “it (multiverse) explains nothing and predicts nothing”, which is not physics argument at all. The only way to counter the multiverse nonsense is by working out the two tasks above with physics.

    Frist, deriving all SM free parameters (see http://prebabel.blogspot.com/2013/10/multiverse-bubbles-are-now-all-burst-by.html )

    Second, deriving all SM fermions (https://scientiasalon.wordpress.com/2014/05/22/my-philosophy-so-far-part-ii/comment-page-2/#comment-2432 )

    With this example, there is no ‘disunity’ in physics but there are ‘wrong’ physics {SUSY, M-string theory and multiverse}. With the G-string unification, the P1 is actually ‘united’ with P2 and P3, in total unity.

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  34. Coel,
    sit down, now hold tight onto your chair.
    I largely agree with you.
    No, I am not going to join the discussion, I have other priorities that claim my attention.
    I just wanted to note this is one of those times that I agree with you. Now take a stiff drink of scotch!

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  35. schlafly, once more, I can assure you that philosophers known prett damn well what they mean by realism and antirealism. I hope your comments will soon graduate from sarcastic-semi-useless to at-least-partially-constructive, because I’m getting tired of them.

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  36. @ SciSal: “Panpsychist, Pigliucci wasn’t arguing that at all. He was simply explaining Fodor’s and Cartwright’s arguments. It is fascinating to me that a number of people here have simply assumed that I defend the positions I wrote about, as opposed to merely entertain the possibility because it opens one’s mind…”

    Perhaps it is becuase of paragraphs such as

    “I would go further than Fodor here, echoing Dupré above: the history of science has produced many more divergences at the theoretical level — via the proliferation of new theories within individual “special” sciences — than it has produced successful cases of reduction. If anything, the induction goes the other way around!”

    which, for this reader at least, seemed to imply you actually agree with these arguments, rather than merely reporting on them. Indeed, even if you were simply reporting on them I would presume that you agree or are at least sympathetic to them unless you explicitly said otherwise. Opening one’s mind is fine and all, but i assume you illuminate content you think may be worth considering.

    To the point: do you in fact agree with something like the above argument, that the greater number of “divergences at the theoretical level” is an empirical argument against the existence of a specific supervenience? Or did you mean that the induction is against “reduction” only in some other (theoretical reduction?) sense? Or were you just reporting on Fodor’s and Dupre’s positions, and elaborating on the actual historical record?

    Or, to ask more broadly – are such anti-reductionist arguments aimed only at “reduction” in senses such as “theoretical reduction”, or do they to target supervenience (or, at least, any kind of specific supervenience) as well?

    @ Miramaxime: “I have come across this statement (or something like this) quite often and I actually don’t see how it follows. It could be that there is “unity to the universe” but the only way to represent this unity is by the universe itself. In my experience it is here that scientists might routinely err uncritically.

    A similar mistake seems to occur whenever Coel (or DisargreeableMe) seem to imply that systems that are describable by some mathematical notation can also be simulated. I don’t see how this follows either.”

    As I am apparently in their camp, I’ll add my voice in defense of their position. So they won’t feel lonely.

    It depends on why “unity” means, really. I take the Regularity (or “Humean”) view of the laws of nature, that sees laws of nature as uniform patterns throughout existence. If there is “unity” in the universe, this means that there really are such uniform universal patterns so that every physical detail is exhaustively described by referring to them (plus initial conditions). If this is the case, in other words if ontological reduction to fundamental physics indeed holds, then it follows that one should be able to describe all the physical state of affairs in the universe and their dynamics in time at this level of description.

    Now, it may be that there are is no finite list of laws of nature, or that the initial conditions are infinitely complex. That would make (finite) computation impossible, but otherwise isn’t really an issue for this worldview. The situation would still be that there is unity in the universe, and everything follows from it. The fact that we won’t be able to finitely caclulate a given phenomena (Godel’s theorem), that we won’t be able to provide a finite full description (not finite list of laws of nature), or to provide a finite description of the universe (infinitely complex initial conditions) won’t change that. Thus, even if the only finite representation of the universe is the universe, the essence of the worldview – seeing the world as unified by physics – isn’t really compromised.

    As for the second point – if the system is truly described by a mathematical notation, this means that there is such a description for the state and the dynamics. It follows that one can calculate future states; that’s what having such a description means! Now it may be that some aspects of the future state are not calculable in a finite way (due to Godel); again, this isn’t a problem for this worldview, it’s simply a limitation on our ability to derive what is true – it’s still true that the Godel sentence is true in this system, even if we can’t prove it.

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  37. @ David: “a complete physical description does not *logically* entail a cheetah’s biological features, aesthetic features etc. Or so say I. I am an anti-reductionist. The reductionist would have to say that a complete physical description would describe *all* of the cheetah’s features. The reasons for thinking thats impossible (multiple realizability, the irreducibility of the normative and telelogical), have been rehearsed here many times before. Whichever side you land on, I don’t think simulation clarifies much.”

    John von Neumann one said “If you tell me precisely what it is a machine cannot do, then I can always make a machine which will do just that.” The reductionist maintains that to the extent that you can tell us precisely what it is that you mean by concepts such as “tooth”, “beautiful”, or so on, we can add sub-algorithms to produce and display this information to the simulation program. You would presumably argue that no “precise” definition in physical terms is possible. I would disagree. But what I hope we can agree on is that if a precise definition in physical terms is provided, then the features would logically follow. This does not mean that a complete physical description describes all the cheetah’s features, however, since these precise definitions aren’t part of the complete physical description, which is given in the reductive terms rather than in the higher-level terms (such as “tooth” or “beautiful”; or “high pressure” or whatever).

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  38. Panpsychist, I don’t find Fodor’s argument to be a knockdown one, but I do tnk it cannot easily be dismissed, at the least if one is serious about paying attention to the empirical evidence. Science is, indeed, becoming less and less unified as time goes by.

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  39. SciSal,

    “Science is, indeed, becoming less and less unified as time goes by.”

    That may be so, but is only one leg of the argument. The major problem with it, as I see it, is the other leg. To put it a bit more formally, the argument seems to be roughly

    (1) Science is becoming less unified as time goes by
    (2) Science would become more unified as time goes by if reduction is true
    Therefore,
    (3) Reduction is false.

    But no one is defending (2). It’s just a non sequitor. From the fact that reduction is true in principle it does not follow that science will become more unified in practice. What is being claimed is more like

    (2′) More and more examples of successful reductive scientific efforts will acccumulate as time goes by; no scientific demonstrations of failure of reduction (i.e. high-level phenomena not obeying low-level laws) will accumulate as time goes by.

    This is indeed the pattern we see – we see people succefully calculating the mass of the proton from particle physics, for example; and we don’t see people demonstrating that particle physics implies a different proton mass than what is actually measured. So the correct induction is overwhelmingly supportive of reduction, and I fail to see why we should not easily dismiss Fodor’s faulty induction.

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  40. Panpsychist,

    “If there is “unity” in the universe, this means that there really are such uniform universal patterns so that every physical detail is exhaustively described by referring to them (plus initial conditions).”
    Really? How do you know? I think you missed Miramaxine’s point. Why not, contrarily, various non-contradictory descriptions of one universe none of which reduce and all of which are sui generis in some way or another? Your point demands argument. Why *must* *your* kind of unity exist?

    “The reductionist maintains that to the extent that you can tell us precisely what it is that you mean by concepts such as “tooth”, “beautiful”, or so on, we can add sub-algorithms to produce and display this information to the simulation program.”
    Perhaps but that might be giving up the game. You could (perhaps) add biological, aesthetic etc concepts to the simulation but unless what you add is completely physical, you are no longer reducing to the physical. You are doing more what we do know which is describing the Cheetah in physical terms when we are interested in its physical properties, biological ones when interested in its biological ones etc etc. But you do anticipate this with your next comment:

    “You would presumably argue that no “precise” definition in physical terms is possible. I would disagree.”
    For me it is not a matter of precision. The teleology inherent in biology prevents biology from being reduced. And so for the normativity in aesthetics and so on.

    “But what I hope we can agree on is that if a precise definition in physical terms is provided, then the features would logically follow.”
    Yes! And that would be successful reduction. But many of us, Aravis most energetically, have given several reasons to doubt that this is possible.

    “This does not mean that a complete physical description describes all the cheetah’s features, however, since these precise definitions aren’t part of the complete physical description, which is given in the reductive terms rather than in the higher-level terms (such as “tooth” or “beautiful”; or “high pressure” or whatever).”
    Here you lose me. To be a reductionist you have to believe the physical description does completely describe the animal (all legitimate description after all “reduces” to fundamental levels.) Frankly I think you, and Coel, often hesitate here because you are not sure if you want to go full reductionism but are uncomfortable with the independence of levels of description inherent in supervenience/emergentism so you try to split the difference and end up in incoherence. If you *really* disagree with me and maintain that all these things can be precisely defined in *physical* terms, you ought to find a physical description complete.

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  41. Panpsychist:

    You are having an argument with an imaginary opponent. Fodor’s argument is not inductive, but based on concrete arguments. When I hear someone give an even remotely plausible reply, I’ll mark it in my calendar. Thus far, however, I’ve heard nothing that even comes close to touching the arguments.

    I’ve rehearsed many of them already — to the sounds of crickets chirping — but will do so again.

    1. Token Physicalism is uncontroversial — and boring.

    2. Ontological reductionism, in the sense meant by those making Unity of the Sciences style arguments, entails Type as well as Token Physicalism. (Coel’s insistence to the contrary notwithstanding — he himself has clearly advocated Type Physicalism … except when he is contradicting himself and renouncing it, as David Ottlinger has patiently pointed out.)

    3. Many, many, special science types/classes/kinds are multiply realizable — that is, they are physically heterogeneous. (My example of currency for instance.) This means that they and the special-science laws in which they figure ARE NOT REDUCIBLE. After all, an indefinite disjunction of possible physical realizations is not itself a type/class/kind of any physical science.

    4. Special science types/classes/kinds/laws/explanations, therefore, are autonomous, vis a vis the physical sciences.

    This rules out *every* reductionist thesis worth stating. (Those it does not rule out are uninteresting and do not advance the Unity of the Sciences view.)

    One more point, to counter the Elminative Materialists:

    5. Special science/types/classes/kinds/laws produce *fruitful* explanations in their relevant domains of application.

    See? No induction.

    ———————————–

    Massimo: Fair enough on your point, re: sincerity vs. ignorance. My suspicions are due, in part, to the fact that we’ve had essentially this argument a half-dozen times on Scientia Salon, and each time feels like Groundhog Day. Since our interlocutors are clearly very smart, one naturally begins to be suspicious…

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  42. Hi Aravis,

    > I find your defense of reductionism the most puzzling, insofar as you are a computationalist.

    I’m not defending reductionism so much as reductionists — my worry is that Massimo seems to be misunderstanding the views of people such as Weinberg, perhaps due to their inability to express what it is they mean with philosophical rigour.

    > And if *this* is true, then psychological laws are irreducible and psychological explanation is autonomous.

    They are irreducible by your’s and Fodor’s and Massimo’s account of reduction. I am not convinced that this is the kind of reductionism espoused by Weinberg (or anybody really).

    The way in which they are reducible is in the supervenience sense, or in the sense described by Coel with reference to simulation. Any model with the right low-level rules necessarily exhibits the right high-level emergent behaviour. The high level behaviour Weinberg-reduces to the low level rules even if it doesn’t Fodor-reduce.

    I have been asking for a source for an unambiguous endorsement of the kind of reductionism this article targets just to settle the question of whether it is a straw man. Perhaps JCC Smart and David Armstrong are good examples, if I can get my hands on the relevant texts. Thanks!

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  43. A purely emotional blurt to begin: I strongly suspect that the intellectual worlds of 100 and maybe of 1000 years from now will almost universally agree that we learned a lot from Steven Weinberg; and that Jerry Fodor will have been completely forgotten (at least at the latter date, hopefully much sooner). But that is no argument for anything at all, so:

    First a simplest form of my questions further down:

    I cannot tell whether you, Massimo, are saying that you have become quite receptive to (1) below, or actually even to (2) (it being strictly stronger in my view).

    (1) The human species will never achieve a theory which is near universally agreed to reduce all of biology and chemistry to physics. (Other parts of science can be ignored to simplify).

    (2) There is no theory which reduces all of biology and chemistry to physics.

    Quite possibly, you disagree with the “stronger” above.

    So I’ll concentrate entirely on the article, though I’ve read responses (to responses to responses, etc.), and learned much, at least about how people here think. So my questions and quibbles are strictly about the article, with my own position, unchanged by reading here, being definitely in favour of reductionism in any sensible form. I’ll soon have both library books, by Cartwright and Dupre, but too late for this. They may change me, but I don’t expect so, from reading the article.

    Pardon my non-use of philosophy terminology (and one must refrain from saying ‘jargon’, but surely there must be a school of non-thought called jargonism).

    I’ll send it in three parts to conform with word limits, and formulate it as questions about specific successive quotes from the article.

    “…attack the idea of reductionism by showing how it doesn’t work in biology.”

    Did you mean to say that no one has yet reduced all of biology to chemistry? ..or that, stronger, no one will ever be able to do that?….or that, much stronger, there could not even exist ‘in the abstract’, quite independently of human access to it, a theory expressible in entirely rigorous language, which amounted to a complete reduction as above? Or that the possible existence of the immediately previous theory is simply meaningless, so the question would not arise? I didn’t see anything further down in the article or responses to entirely clarify the matter, but perhaps some terminology of philosophers simply passed over my head. If the latter, please alert me to it, and I’ll get busy with more reading.

    To be clearer about my own ‘sentiments’, and this may be unsurprising in view of a few earlier things I’ve written here, I would say the latter is meaningful, not meaningless.

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  44. (con’t from above)

    “…there are a number of perfectly equivalent ways of thinking about the universe and its furnishings”

    Without any details of this, the sentences preceding this are clearly an unconvincing argument by popularity, or by democracy, or whatever phrase philosophers use for this fallacy. But, anyway, are these “ways of thinking” all within physics, and, if so, is it simply the categorical equivalence of quite different looking categories of mathematical structures which is being referred to? I suspect not, in which case would some such non-physics “way” be a way of considering the entire universe sensibly entirely within chemistry, or within biology, or…? Nice to see an example, and maybe even an explanation of something so mundane as thunder/lightening entirely in terms of biology or whatever, or even the much less mundane microwave background explained in terms of sociology, say.

    “…the natural sciences form a hierarchy of fields and theories that are (potentially) reducible to each next level, forming a chain of reduction that ends up with fundamental physics at the bottom.”

    This is a minor point, but I don’t think anybody gets too excited about reduction being a (mathematical) chain rather than more generally a (mathematical) tree, but with a unique (physics we call it in these early days) root.

    “…scientific theories are not “out there in the world,” so to speak, they are creations of the human mind..”

    This is asserted baldly, to attempt to make clear some (still unclear me) distinction between ontological and theoretical reduction. It does signal to me the probability that you would agree with the “meaningless” statement I disagreed with above. I was bit surprised by this, given that you are not entirely negative about the ideas of Ladyman et al. But probably I’m just misunderstanding the book by the latter, though I’ve worked hard at several sections in it!

    “…most philosophers of chemistry think that a stronger conception of unity is mistaken. Most believe that chemistry has not been reduced to physics nor is it likely to be.”

    I looked through the Stanford blurb, and for me it goes in near the bottom end of my ranking of that Encyclopedia as being extremely uneven in general. At least there, as opposed to wiki, one knows who wrote the various articles; but wiki is sometimes to me far superior. Your quote immediately above reinforces my feeling that you would disagree with me that it is sensible to consider the possibility of a theory really existing which might for some reason by inaccessible to humans, even after unrealistically assuming no upper limits on either the lifetime of the species nor on quantitative improvements in its abilities to explain scientifically. The quote itself, taken with surrounding writing, does however give no idea to me of what the distinction is when it refers to a “stronger conception”. I know you didn’t write it, but having quoted it, maybe you could clarify what, to you, that conception could possibly mean.

    “…the Superconducting Super Collider… the proposed antecedent of the Large Hadron Collider…”

    Again very minor, IIRC the former would have produced larger energy with collisions, so “antecedent” is probably misleading, though not really germane here. But the implication that Anderson disbelieved in reductionism as a theoretical likelihood is false, I think. His motivation for opposing spending so much money on the SSC was not that.

    “…’the less relevance they seem to have to the very real problems of the rest of science.’ So much for a fundamental theory of everything.”

    This is the first of a couple of attempted implications that seeking a “final theory” (as Weinberg dreamed it) is somehow tightly connected to the question of reduction. I see no reason that the nonexistence of either should imply the nonexistence of the other. The existence of reduction seems far more likely than that of a final theory, but the latter is far from discounted in my mind.

    (con’t below)

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  45. (con’t from above)

    Your numerical example gives another illustration of something referred to above by me. Here are three propositions related to it:

    ‘There is a sequence with length 12,978,189 of digits which decimally denotes a certain more succinctly specified prime number.’

    ‘I won’t, but I could in principle, write down that sequence.’

    ‘Here I proudly present that sequence____…____’

    In that example, the first of these follows from either of the other two of course.

    However

    ‘There is a function to the 2-element set {true, false} from the set of sentences in the language of 1st order number theory, a function which gives correctly the truth or falsity of its input applied to that mathematical structure which is the standard natural numbers.’

    ‘I won’t, but I could in principle, write down an algorithm which computes that function.’

    ‘Here I proudly present that algorithm for your delectation in a software language of great beauty.’

    Perhaps in a more general form (the Entscheidungsproblem), as any of your readers who have studied logic even only up to an elementary 30 lecture course (logic as understood for the last 80 years) should know, the 2nd and 3rd of these are dead false, even though the 1st is true. They will also know there is an algorithm listing all the true sentences, despite the 2nd being false. (If they never learned it, the philosophy prof who failed to properly educate should be kept away from students till after furthering his own education!)

    I think belief in the truth of the 1st one just above bears some analogy to belief in possible existence of theories which are permanently inaccessible to humans, but ones whose existence can be quite cogently argued for.

    Pardon the length, but to illustrate this, and to finish by going back to people who seem to assert that chemistry does not reduce to physics, I assume that each of them has a relevant candidate proposition in the quantum field theory known as the standard model of particle physics, a proposition about the particles which underlie these philosophers’ scientific subject matter of chemistry, believed of course by particle physicists, but which must be false. Hopefully they have informed the Large Hadron people, so that an experiment can be concocted to actually produce that falsification they are claiming must exist, once the machine gets running again in May.

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  46. Sorry, I meant to write ‘there is an algorithm listing all the ‘deducible from an axiom system’ sentences”
    Obviously ‘true’ is not the correct word there. Good thing I’m not teaching that stuff tonight or any time soon!
    I’ve only got one more kick of the can now.

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  47. Throughout the comments here, we have largely discussed arguments presented in the article, it’s references, and directly related theoretical material. That is entirely proper. But I thought it might be well, to remark how unification reduction might look in actual practice. I think it looks like this:

    “The beauty of the mind of man has nothing to do with free will or any unique hold that biology has on select laws of physics or chemistry. (…) The reality is, not only do we have no more free will than a fly or a bacterium, in actuality we have no more free will than a bowl of sugar. The laws of nature are uniform throughout (…).”
    “Whatever the complexities of the molecular details of consciousness are, they are unlikely to involve any new law in physics that would break the causal laws of nature in a nonstochastic way.”

    This is Anthony Cashmore, a molecular biologist at the University of Pennsylvania, in an incompatibilist determinist argument against free will, in relation to sentencing of criminals in the American justice system. The implication of his text is clear: the laws of physics *are* the laws of biology; assuming otherwise (certainly in anyway that might allow for a compatibilist position on determinism) is really simply a surreptitious vitalism. The sciences are already unified, it all reduces to physics. (The greater implication of his text is that we should reconstruct society around this unification, beginning with – explicitly – the American justice system.)

    Cashmore is obviously not attempting to break the “unique hold that biology has on select laws of physics.” On the other hand he does seem to imply that biology has no special laws of its own. For Cashmore, physics determines chemistry, chemistry determines genetics, genetics determines physiology, physiology determines behavior. This linear determination is absolute. Special sciences may only form subdivisions of physics; biology itself may be simply a subdivision of physics.

    I am rather amused that human behavior is as predictable, under this schema, as a bowl of sugar. Whether the bowl of sugar feels the same way, I have not inquired. However I am not going to bother with the compatibilism/ incompatiblism issue here.

    But I am concerned with the dangerous lack of distinction, the lack of any sense of the subtle differences, not only in differing theories and differing sciences, but in differing practices in differing sciences. This just seems impoverished to me. I like variety and complexity. One thing we learn from evolution is that diversity is (usually) a good thing; it opens opportunities for survival, and generates techniques and mechanisms for further development in the future. Loss of complexity, overly concentrated centralization, conformity to inflexible schematics, all generally endanger populations in environments requiring change.

    Heck, given arguments over string theory and multiverses, unresolved problems between quantum theory and larger systems mechanics, the concern over the dark matter phenomenon, even physics doesn’t seem reducible to physics anymore.

    *http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842067/
    See also Henrik Anckarsäter’s rebuttal, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906598/.

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  48. Miramaxime: “… with physicists a “theory of everything” would simply comprise the theoretical possibility to describe the universe at a given time by a state vector of fundamental entities …”

    Yes, this is the sayings of M-string physicists.

    Miramaxime: “… I never heard a physicist voice the opinion that everything that can be observed in the universe on any level of observation would need to be deductible or explainable on this basis (or at least I never understood physicists to say so).”

    My 3P comments at this Webzine made very clear that ‘all’ in this universe are the emergent of the Nature-physics (different from the human physics). This is also the ‘key’ issue in the book “Super Unified Theory (copyright TX 1-323-231)” which is in the archive of ‘inspirehep’ and available in my university libraries (see https://scientiasalon.wordpress.com/2014/11/24/infinities-in-literature-and-mathematics/comment-page-1/#comment-9782 ). Now, you have it.

    Of course, I did not and will not use the term ‘reductionism’ as it carries too much baggage with different connotations and interpretations. Furthermore, there are huge differences between reduction in concepts, in processes and/or in substances.

    The emergences are constructed with ‘similarity transformations’ (not reductions): with linkages, bridges, connections. That is, different systems are linked with ‘isomorphic’ structures, not direct reduction. And, I showed one example of this: the P1, P2 and P3 are all described with 7-code systems while there is no need of any direct ‘reduction’ among these three 7-code systems (see https://scientiasalon.wordpress.com/2014/11/24/infinities-in-literature-and-mathematics/comment-page-1/#comment-9777 ). In this example, the {A, G, T, C,…} did not ‘reduce’ to {red, yellow, blue, white (quark colors),…}, but they two are isomorphic systems.

    This issue can actually be addressed with three step.

    One, the Nature is a Unity.
    Two, Zen Buddhism accepts that this Nature is a Unity but is unreachable by ‘language’.
    Three, Sciences describe this Nature in ‘pieces’ which seemingly have no linkages among them. That is, sciences are diverging.

    As sciences are based on the phenomenological laws, their divergences are the necessary consequence. Yet, all phenomenological laws are the expressions (emergent) of some fundamental laws. Yes, this phenomenological to fundamental can be defined as ‘reduction’. Often, two sets of fundamental laws are in general not able to be reduced to one or to the other ‘directly’. But, as long as these two sets are isomorphic to each other, they have been reduced to ‘each other’ (not to one or to the other).

    Yes, sciences are diverging with the phenomenological laws.
    Yet, the fundamental/emergent force converges them.
    Then, the final ‘isomorphism’ (not reductionism) unifies them all.

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  49. Alexander, the anti-realist explains empirical adequacy independently of truth on the grounds that theories are empirically adequate because they have been selected for being so. Since theories can be underdetermined by the evidence, a theory can be adequate and yet false. Newtonian mechanics is the obvious example: its picture of space-time is considered wrong nowadays, and yet, if you want to send a rocket to the moon you still use it, and not quantum mechanics.

    Yes, but the realist also knows and admits that theories are only approximations of reality. Newtonian physics really is a good example: calling them wrong is a rather strange use of the word wrong. They are “true enough”, and I just don’t see the difference to “adequate enough” because one couldn’t assess adequacy except against the dimly glimpsed outlines of the true nature of the universe.

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  50. “Theoretical reduction was, of course, the holy grail (never achieved) of logical positivism: it is the ability to reduce all scientific laws to lower level ones, eventually reaching a true “theory of everything,” formulated in the language of physics.”

    If I may,

    The solution to Einstein’s Unified Field Equation:

    e = mc2
    e = m
    =

    Grand Unification!

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