The annual Stoic Week is approaching , so it seems like a good time to return to my ongoing exploration of Stoicism as a philosophy of life. I have been practicing Stoicism since 4 October 2014 , and so far so good. I have been able to be more mindful about what I do at any particular moment in my day — with consequences ranging from much less time spent on electronic gadgets to more focused sessions at the gym; I have exercised self-control in terms of my eating habits, as well as with my emotional reactions to situations that would have normally been irritating, or even generating anger; and I feel generally better prepared for the day ahead after my morning meditation.
I have also spent some time reading Stoic texts, ancient and modern (indeed, I will probably offer a course on Stoicism “then and now” at City College in the Fall of ’15. Anyone interested?). Which in turn has led to an interest in exploring ways to update Stoicism to modern times not only in terms of its practice (where it’s already doing pretty well), but also its general theory, as far as it is reasonable to do so.
Now, before proceeding down the latter path, a couple of obvious caveats. First off, as a reader of my previous essay on this topic here at Scientia Salon  pointedly asked, why bother trying to develop a unified philosophical system? Isn’t life just too complicated for that sort of thing? To which my response is that any person inclined to reflect on his life strives for a (more or less) coherent view of the world, one that makes sense to him and that he can use to make decisions on how to live. One may not label such philosophy explicitly, or even think of it as a “philosophy” at all, but I’m pretty sure the reader in question has views about the nature of reality, the human condition, ethics, and so forth, and that he thinks that these views are not mutually contradictory, or at the least not too stridently so. In other words, he has, over the years, developed a philosophical system. Indeed, I would go so far as saying that even not particularly reflective people navigate life by way of what could be termed their folk philosophical system, whatever it happens to be. Why, then, not try to develop one more explicitly and carefully? And if so, Stoicism happens to be a good starting point, though by far not the only one (I have in the past played with Epicureanism, and also — in the specific realm of moral philosophy — with virtue ethics; other non religious people have adopted secular humanism, of course, or even secularized versions of Buddhism ).
Second caveat: beware of changing and re-interpreting things so much that what you are left with has little to do with anything that can reasonably be called Stoicism. This is indeed a danger to keep in mind, but it is often overstated. To begin with, philosophies (and religions!) naturally evolve over time. Even during the classical Stoic period scholars recognized significant differences between the “Old Stoa” of Zeno and Chrysippus (3rd century BCE), the Middle Stoa of Panaetius and Posidonius (2nd and 1st centuries BCE), and the late Stoics of the Roman empire, like Epictetus, Seneca and Marcus Aurelius (1st and 2nd centuries CE). Moreover, no modern philosopher would (or should) adopt the early version of anything his predecessors have proposed, because, you know, philosophy makes progress ! That’s why Philippa Foot , for instance, was talking about neo-Aristotelian virtue ethics, not the original version by Aristotle himself; or, to take another example, Peter Singer  considers himself a utilitarian, but not in the same sense of Jeremy Bentham, or even John Stuart Mill. Similarly, what I’m going after is some kind of neo-Stoicism, inspired by, and as close as possible in spirit to the original, but updated with all the science and philosophy of the many centuries separating us from Marcus Aurelius.
All right, then, let’s get back to work. The inspiration for what follows was provided by a short article on the system of Stoicism by Donald Robertson , and more broadly by Pierre Hadot’s The Inner Citadel (cited by Robertson) .
Stoics used a number of metaphors to explain how they thought of philosophical inquiry. My favorite is that of the egg (see figure): the shell corresponds to what the Stoics called “logic,” but which is better understood nowadays as the study of reason broadly construed, to include also a theory of knowledge. The white interior, the albumen of the system, so to speak, is occupied by “ethics”, which for the Stoics, just like for most of the ancient Greek-Romans, meant not just the study of right and wrong, but more broadly knowledge of what kind of life we want to live and society we want to build. The yolk, then, is what Stoics called “physics,” but that in modern parlance really is a combination of all the natural and social sciences, as well as metaphysics. (Henceforth, the term “physics” is the only one I will keep putting in quotation marks, to remind the reader that it refers to something significantly broader than its modern equivalent; I’m happy to keep using ethics and logic without that warning, as the modern meanings of those terms are not too terribly remote from their Stoic sense.)
The Stoics actually disagreed on whether logic or “physics” should be the central topic (apparently, ethics was always in between), but I’ll stick with that view, which also makes the most sense to me. What is the point of the metaphor? To illustrate the idea that the different parts of philosophy (really, what today we would call “scientia”) are interdependent and should not be studied in isolation. If one is concerned with ethics — which many Greek-Roman thinkers thought of as the most important part of philosophy, because it applies directly to human life — one isn’t going to do a good job unless one can reason properly or knows the relevant facts about the universe (physics, metaphysics) and humanity (biology, social sciences). Hence the egg: ethics floats in between the hard shell of logic and the soft core of “physics.”
Before moving to the other components of my little concept map, a few words on beginning to update Stoic logic and “physics.” I will refer the interested reader to the very detailed entry on Stoicism in the Stanford Encyclopedia of Philosophy , but I will also add that I don’t think a neo-Stoic needs to be bounded by the specifics of what the ancients thought about either of these two parts of philosophy, just like a modern Buddhist isn’t bound by everything that has been written in the ancient Buddhist canon (one is, however, bound by Stoic precepts on ethics, which was much more central to their philosophy from the beginning, and became even more so during the Roman period). I say this because there is plenty of evidence that the Stoics themselves modified their views over time in response to criticism from rival schools, particularly the Skeptics, and I don’t see why the process has to arbitrarily stop with the Fall of the Roman Empire.
Still, let’s take a quick look at some of the basic characteristics of Stoic logic and “physics,” and how we can make sense of them. Beginning with logic, then, the Stoic approach was focused on propositions, rather than terms, which made it distinctive from Aristotelian logic, and much more akin to modern propositional logic, particularly the work of Gottlob Frege. Stoics also developed a system of deductive logic, thanks in large part to Chrysippus, that represented an alternative to the Aristotelian approach.
I find it interesting that the Stoics thought that there was a sensible distinction to be made between concrete bodies and abstract entities, while at the same time rejecting the idea of incorporeal beings (which was accepted by Aristotle, and of course later on by the Christians). This is compatible with a modern kind of varied ontology, one that reserves material existence for objects while acknowledging “existence” of some types of things like concepts, mathematical structures, and the like. I myself am pretty happy with this sort of pluralist ontology, being a naturalist more than a strict physicalist.
Within their concept of logic the Stoics included a theory of knowledge, which was based on the idea that reason can — aided by the senses — lead us to at the least approximate truths. They also thought that we are capable of passing judgment on our “impressions” of the world, distinguishing correct ones from incorrect ones. Modern cognitive science has significantly diminished the scope of right judgment that human beings are capable of, but the fundamental idea is that we can reason on whether or not we have formed a correct representation of reality, without which assumption even modern science (including research on cognition) would go out the window. Stoics, in a remarkably modern fashion, acknowledged a continuum of reliability of our judgments, with the highest degree of knowledge achievable only through the use of expertise and the collective effort of humanity . Again, the details are historically interesting, but need not be imported wholesale into any form of neo-Stoicism. What is important, in my mind, is an appreciation for the general spirit of inquiry, the reliance on reason and empirical evidence, and the crucial idea of expert peer judgment, all of which fit rather well with our modern conception of rational and scientific investigation.
What about Stoic “physics” (i.e., natural and social science, as well as metaphysics)? The Stoics were materialists who believed in universal cause and effect, so in that sense their natural philosophy has little difficulty being updated to our modern conceptions of physicalism (or, for me, naturalism) and even determinism (on the latter point things are a bit ambiguous, as some Stoic writings confuse the concept of fate with that of universal cause and effect, they need not be the same).
However, Stoics also believed in Logos, a rational principle underlying the functioning of the universe. Now, they referred to Logos also as Zeus (God) or Nature, which leaves room both for a compatibility between Stoicism and some religious traditions (e.g., Christianity), or an entirely atheistic view of the cosmos . (Incidentally, I find the similarities and compatibilities between Stoicism and other philosophical and religious doctrines, such as both Christianity and Buddhism, an unqualified plus.)
There are two modern interpretations of Logos that can be proposed, one rather uncontroversial, the other more radical. The uncontroversial way of looking at the Stoic Logos with modern eyes is something analogous to Galileo’s famous statement that the book of nature is written in mathematical language: the universe really is structured according to logical principles, which is what makes it (partially) understandable by human beings deploying the tools of reason, science and mathematics. This line of reasoning could even be pushed a bit further, ending up in a claim similar to the idea of ontic structural realism advocated among others by James Ladyman : at bottom, there are no particles or “things,” the fundamental structure of the universe just is mathematical relations. The more radical version of this is that the underlying reason for the logic of the universe is that we live in something like Max Tegmark’s mathematical universe , or even inside one of Nick Bostrom’s simulated universes . I’m not going that far myself, preferring instead the solid Galileian ground. Still, it’s fun to think about the other possibilities as well.
And so we come to ethics and the remainder of my concept map. You will notice that the different parts of the egg are connected to three of the fundamental Stoic virtues (justice, self-control, and wisdom ), which in turn are linked to the three Stoic disciplines described by Epictetus (Action, Desire, and Assent). Let’s see what that’s all about.
The most obvious and self explanatory connection is between the study of ethics and the virtue of justice. The latter, in turn, is linked to the discipline of Action, which for Epictetus consisted in making sure that we act in accordance with our duties, beginning with those imposed by our natural (i.e., family) and acquired (i.e., friends and other human beings) social relations. And let’s not forget that Stoic ethics included the principle of an expanding circle of concern, which is supposed to extend to all humanity, and even to nature as a whole.
But what is the connection between “physics” (i.e., science broadly construed, to include metaphysics) and self-control? Here, I take it, the idea is that science also teaches us broadly about what is physically possible and impossible and specifically about human nature, and therefore allows us to understand, relate to, and act on human desires. It is this understanding that makes self-control possible, and the discipline of Desire is how we teach ourselves what is good to seek and what is best to avoid, in accordance with human nature and — even more broadly — with humanity’s place within the cosmos. (The latter need not be teleological, as the Stoics did believe it was; it can simply mean an understanding of humanity within the context of a physical universe and its laws.)
Finally, we have the link between logic and the virtue of wisdom, because wisdom comes from rational reflection on our experiences. This, then, is connected to the discipline of Assent, which is the one through which we develop the ability to discriminate what is (likely) true from what is not, or to suspend judgment if we cannot arrive at a reasonable conclusion.
The very fact that the three parts of Stoic philosophy are all connected not just to each other, but to virtues and disciplines underscores once more the idea that for the Stoics it was ethics that was the central concern of philosophy, with other types of inquiry (including science, in modern parlance) needed as aids to develop knowledge of how to live. Which seems a fine concept to me.
Now, the above may not be your cup of tea, of course. But I think it represents at the least the beginning of an attempt to update the whole of Stoic philosophy into a version that is compatible with modern science (and philosophy) and still useful and meaningful for 21st century human beings. This is no different, really, from ongoing attempts at secularizing, say, Buddhism (or even, more controversially, Catholicism), to provide a system of beliefs and practices that can be adopted by people in search of reasonable alternatives to religions but who are turned off by the incipient nihilism  of straightforward atheism (especially of the currently popular, strident variety).
As I’ve said for a long while now, there is a rich middle ground between religions and atheism, a middle ground occupied by a number of philosophical systems — including, but not limited to, Secular Humanism, Buddhism, Confucianism, Epicureanism, and of course Stoicism. And as philosophies go, one that says, as Epictetus famously did in the Discourses, “What, then, is to be done? To make the best of what is in our power, and take the rest as it naturally happens,” is most certainly not a bad one.
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).
 Stoic Week 2014: Everything You Need to Know.
 How do I know? Because that’s the date of my first entry in my evening meditation diary, which is one of the regular practices of a Stoic, according to the Stoic Week handbook.
 Why not Stoicism?, by M. Pigliucci, Scientia Salon, 6 October 2014.
 See, for instance: The Bodhisattva’s Brain: Buddhism Naturalized, by O. Flanagan, 2013.
 I have just finished writing a book on this topic, hopefully to be published soon by Chicago Press.
 See: Virtues and Vices: And Other Essays in Moral Philosophy, by P. Foot, 1979.
 For instance: How Are We to Live? Ethics in an Age of Self-Interest, by P. Singer, 1994.
 The System of Stoic Philosophy, by D. Robertson, Stoicism and the Art of Happiness, 18 October 2012.
 The Inner Citadel: The Meditations of Marcus Aurelius, by P. Hadot, 2002.
 Stoicism, by D. Baltzly, SEP.
 The “ideal Sage” was supposed to be capable of perfect knowledge. Then again, unlike the case of religions such as Christianity and Buddhism, the Sage was never meant to be thought of as a real person (let alone a God), or even as something a real person could possibly become. It was rather an ideal to constantly strive for.
 Incidentally, by “Zeus” the Stoics most certainly didn’t mean that popular image of a lascivious god who kept taking animal form in order to seduce and have sex with a number of unsuspecting (and characterized by rather bizarre sexual tastes!) human females.
 James Ladyman on Metaphysics, Rationally Speaking podcast, 8 September 2012.
 Max Tegmark on the Mathematical Universe Hypothesis, Rationally Speaking podcast, 8 February 2014.
 David Kyle Johnson on the Simulation Argument, Rationally Speaking podcast, 28 April 2012.
 The forth cardinal virtue, courage, is often associated with self-control, as to be courageous means to control one’s fears.
 Nihilism, Rationally Speaking podcast, 2 November 2014.