This session of the Eastern Division meetings of the American Philosophical Association (part of my ongoing series of commentaries on the meeting) was chaired by Emily Parke (University of Pennsylvania), and the speakers were Mark Bedau (Reed College) and Paul Humphreys (University of Virginia).
Bedau’s talk was far easier to follow, so I apologize if I have not been able to do justice to Humphreys, though in the end I think I got where he was going…
Briefly, Bedau wants to reframe the debate about emergence. It is usually presented as an attempt to understand the true nature of emergence, which implies that if one’s view of it is right the other one has to be wrong, which leads to acrimony and generally unproductive discussions. Bedau favors instead a type of pragmatic pluralism about emergence.
He proposed that there are two hallmarks of emergence: the whole depends on its parts, but it is also somehow autonomous from its parts — the problem is that the two at the very least seem inconsistent with each other, so that we need a way to reconcile or resolve such apparent inconsistency.
For Bedau emergence can be weak, nominal, or strong (and then there is a fourth type to be addressed later), depending on how the dependance / autonomy relationship between wholes and parts is supposed to work. A pluralist project has to ask whether the dependance and autonomy hallmarks in any particular concept of emergence are in fact inconsistent: if they are, that concept is out. But, depending on how the two are cashed out, there are a number of ways of making them not mutually contradictory. A second pluralist test for any given concept of emergence has to do with whether there are real examples of the types of emergence being examined (if not, then the concept is provisionally ruled out).
Bedau then introduced the concept of bottom-up whole: the idea that the whole is nothing but the organized combination of its parts. An example is provided by enclosed vesicles that spontaneously form when certain lipids are dropped in an aqueous environment, well known from biophysics: the whole looks a lot like a cell membrane and displays membrane-type “holistic” properties, but is also made of a countable and known number of individual components, assembled in a particular fashion. Another example is cellular automata: we write the program, so we know exactly how it works, what rules determine the behavior of the system, and how many pixels form each cellular automaton evolving on the screen. Nonetheless, the automata also have ensemble-level properties, such as movement (the automata “move,” not the individual pixels).
Let me now turn to Bedau’s classification of the three basic types of emergence, as he sees them:
whole-part dependence > properties of wholes supervene on properties of parts
autonomy of the whole > properties of the whole are undefinable by / irreducible to properties of the parts
examples > conscious minds?
Bedau thinks this is a coherent concept (I don’t, as I see inconsistency between the ways in which whole-part dependence and autonomy of the whole are defined), but he claims that there are no actually well understood real examples of it. The conscious mind, the only example usually brought up in this context is very much under question, and to accept it without further analysis would come close to begging the question.
whole-part dependence > bottom-up whole, as defined above
autonomy of the whole > the concept applies only to wholes, some properties of wholes are undefined for parts (e.g., “gliders” in the game of life move around, have speed and direction, but individual cells don’t, as mentioned above)
examples > cellular automata, lipid layers, lots of others
whole-part dependence > bottom-up whole, as above
autonomy of the whole > patterns of behavior of whole caused by incompressible causal web among its parts (i.e., brute-force calculation is required to go from behavior of parts to behavior of whole)
examples > some types of cellular automata, those for which one cannot tell arbitrarily far into the future what is going to happen by just examining the meaning of the rule (i.e., not trivial automata); lots of others
At this point one of the attendees commented that it looks like what the author calls bottom-up whole is actually indistinguishable from supervenience . I think she was right. Also, Bedau used essentially the same examples to illustrate normal and weak emergence: traffic jams, vesicles, protocells, origin of life, cellular automata, and agent-based models, thus introducing a palpable degree of confusion between the two concepts.
Now to the forth kind of emergence, which seems to be original with the author: he called it continual creative emergence. Examples include complex life forms, mind, culture, and technology. It is characterized by autonomous “door-opening” processes (e.g., a biological or technological innovation) whereby new and more complex kinds of wholes emerge over time. It is also characterized by iterations of higher-order nominal and weak emergence.
I think I know what Bedau means here. The phenomena he is referring to are often described as “major transitions” in evolution , and include for instance the origin of cells, of multicellularity, and of language, among others. They are best understood — biologically — as transitions made possible by changes in multi-level selection dynamics, as postulated by Samir Okasha . I do agree that they also represent interesting examples of emergence, though whether they are best characterized the way Bedau did remains to be seen.
Essentially, Bedau was attempting to make room for less acrimonious and more constructive discussions of the various concepts of emergence on the table, a laudable goal to be sure, though of course there may be other ways of being pragmatic, as he put it, or even ecumenical, about it.
Humphreys talk was on what he termed “transmutational emergence” and much of what follows comes straight from the author’s handout at the talk, which was fairly dense and difficult to follow (no slides!). The author began by pointed out that the philosophical literature on emergence has recently focused on synchronic emergence and compositional ontology, maintaining that a lot of resistance to emergence depends on a number of commitments and inclinations: endorsement of fundamental physicalism, causal closure of the physical domain, the deployment of supervenience, and a sense that emergence is “scientifically superfluous.”
Humphreys suggested that some of the open issues may be ameliorated by paying attention to diachronic emergence. He also proposed that there are several kinds of emergence, and that paying attention to mental phenomena (a very common approach) is a bad move precisely because it is so controversial and one risks begging the question in reaching one’s conclusions. On this, as we have seen, he agrees with Bedau.
It is a common assumption in discussions of emergence that the constituent parts of a whole are synchronically and diachronically stable, meaning that if taken apart they would retain their identity, and that such identity does not change over time. The latter, according to the author, is not always the case.
Humphreys proposed a number of criteria to identify emergence: the emergent entity has to be novel, it is autonomous from its origins, it results in some way from the dynamics of its original domain (after all, it “emerges” from something!), and some holistic feature is present.
The first example of diachronic emergence presented by Humphreys is admittedly artificial: he called it checkers world. Consider a universe that looks like a checkers board and imagine that the rules of the game are actually laws regulating interactions between white and black “particles” in that universe. The individual particles are immutable, in the sense that their properties remain the same regardless of the state of the system (though any given particle may be able to exercise a property only in certain circumstances, like annihilating a different color particle if it is in its proximity, etc.).
Now imagine that — unlike the case of actual checkers — the rules of checkers world allow for the evolution over time of new kinds of particles (say red and blue), and that the new particles follow different rules of behavior. The idea is that the properties of the later universe cannot be predicted from the laws regulating the initial black/white universe, unless one also knows the additional law(s) that made the transition to the new universe possible. (Note that the original laws are still active, but after a while there are no longer any black and white particles to instantiate them.)
The second example was drawn from real science, but the author labelled it as tentative: the Standard Model of physics includes a certain number of particles (six quarks and their anti-particles; six leptons and their anti-particles; and four force carrying particles; plus the Higgs boson). Leptons and quarks are non-composite, they are really fundamental. Interestingly, however, they decay, i.e. they diachronically transform into other particles (e.g., a charm quark transforms into a strange quark plus a W boson, and the latter then transforms into up and down quarks).
Humphreys suggested that there is a parallel of sorts with checkers world, with fundamental entities that do not synchronically supervene on anything, and yet transform themselves into other fundamental entities over time. Also note that quarks are not found in isolation, which means that their properties cannot actually be maintained when the entities are considered in isolation (because they are never found in such state).
His third example was a classic one in discussions of emergent behavior: mobs. This is a loosely structured group of humans displaying socially disruptive behavior. Mobs have distinct group-level properties, such as levels of violence, and the discussion usually is on whether these properties are or are not reducible to the properties of individuals, with some authors suggesting that the group-level behavior might best be described by (irreducible) sociological laws that are distinct from those (psychological) describing the behavior of individuals.
But here Humphreys proposed that a better way of looking at mobs is that the properties of the group (and of the individuals interacting within the mob) change over time during the evolution of the system. Rather than invoking sociological holism, one can focus on the temporal psychological transformations of the individuals, who experience diminishing levels of rationality and increasing levels of violence, while at the same time of course maintaining physical individuality.
Interestingly, the case is different from, say, that of flocks of birds, or crowds of humans. In these latter instances, the psychological characteristics of the individuals do not change over time (well, at the least for humans, we don’t really have much access to the psychology of birds).
In conclusion, according to Humphreys, it is useful to distinguish dynamic from simple fundamentality: the first one requires that “a fundamental object, a property, or a fact must be present during the initial state of a system”; the second one requires that “an object, property, or fact not have components,” and the two are logically independent. Since the laws operating at the initial state of a system (checkers world, the universe, the crowd about to turn into a mob) may not fix the laws at all times, there is a distinction between causal closure and nomological closure.
I wish there had been time to explore this idea of a (possible) distinction between causal and nomological closure, which obviously connects with our discussion of causality in physics vs the special sciences from a few days ago , but that’s the best I can do to summarize the session, I’m afraid.
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).
 Supervenience, Wiki entry.
 The Major Transitions in Evolution, by J. Maynard Smith and E. Szathmáry, Oxford University Press, 1998.
 Evolution and the Levels of Selection, by S. Okasha, Oxford University Press, 2007.
 APA 2014-2: Against causal reductionism, by M. Pigliucci, Scientia Salon, 31 December 2014.