The complex relationship between metaphysics and ethics

The point of Stoic philosophy is to help us live a worthwhile life. That task fell to one of the three Stoic fields, i.e., areas of study, known as the ethics. But the Stoics insisted that in order to improve our understanding of ethics we also need to learn about the other two fields, “physics” and “logic.” Physics actually encompassed what we today would call the natural sciences (including physics in the modern, narrow sense, of the term), metaphysics, and theology. Does that mean, then, that Stoic ethics is compatible only with a particular type of metaphysics or theology? I have argued in the past that this is not the case, and have reiterated the notion more recently, when discussing the difference between pantheism and panentheism. But if so, doesn’t that mean that the ancient Stoics were mistaken in linking their physics to ethics? And wouldn’t that, in turn, make their ethics far less naturalistic than it seems to be? I’m going to explain in this post why that is not the case either: Stoic ethics is compatible with some, but not all, possible metaphysics, thus confirming the ancient intuition that we ought to know something about how the world works in order to live the best life possible, and also that modern Stoicism is an ecumenical philosophy, within certain limits.

Thesis 1: multiple metaphysical views are compatible with Stoic ethics

The idea that more than one approach to metaphysics is compatible with Stoic ethics is actually well established by the Stoic texts that have arrived to us, and so shouldn’t be too controversial. Here are some examples:

“Whether Fate binds us down by an inexorable law, or whether God as arbiter of the universe has arranged everything, or whether Chance drives and tosses human affairs without method, philosophy ought to be our defence.” (Seneca, Letters to Lucilius, XVI. On Philosophy, the Guide of Life, 5)

“Death either annihilates us or strips us bare. If we are then released, there remains the better part, after the burden has been withdrawn; if we are annihilated, nothing remains; good and bad are alike removed.” (Seneca, Letters to Lucilius, XXIV. On Despising Death, 18)

“About death: Whether it is a dispersion, or a resolution into atoms, or annihilation, it is either extinction or change.” (Marcus, Meditations, VII.32)

“Either all things proceed from one intelligent source and come together as in one body, and the part ought not to find fault with what is done for the benefit of the whole; or there are only atoms, and nothing else than mixture and dispersion. Why, then, are you disturbed?” (Marcus, Meditations, IX.39)

“Whether the universe is a concourse of atoms, or nature is a system, let this first be established: that I am a part of the whole that is governed by nature; next, that I stand in some intimate connection with other kindred parts.” (Marcus, Meditations, X.6)

While most of the Stoics were pantheists, there have been Christian Stoics, and obviously there are nowadays agnostic and atheist Stoics. In any case, the above quotations establish beyond reasonable doubt that the ancient Stoics themselves did not think there was a contradiction in adopting diverging metaphysics (“whether the universe is a concourse of atoms, or nature is a system…”) and behaving according to Stoic ethical precepts (“… let this first be established…”).

Thesis 2: not all metaphysical views are compatible with Stoic ethics

If we accept the above, however, we run into the unfortunate possibility of rejecting the very idea that one needs to study the three fields in order to make sense of ethics. If multiple, diverging, metaphysical views are compatible with Stoic ethics, then why study “physics” at all?

There are two non-mutually exclusive answers to this. The obvious response is that Stoic physics isn’t limited to metaphysics. It also includes all of the natural sciences, and a study of the natural sciences will still be useful to figure out how to “live according to nature.” Here is Cicero on this:

“The Chief Good consists in applying to the conduct of life a knowledge of the working of natural causes, choosing what is in accordance with nature and rejecting what is contrary to it; in other words, the Chief Good is to live in agreement and in harmony with nature” (De Finibus III.31), and living according to nature means specifically human nature, which the Stoics thought is the nature of a social animal capable of reason. Hence Seneca’s advice: “Bring the mind to bear upon your problems” (De Tranquillitate Animi, X.4).

The idea is that if the study of the natural philosophical component of physics told us something very different, then this would be affecting the proper way to think about ethics, quite regardless of the metaphysical (or, for that matter, the theological) component of physics.

The second, and more interesting, reason why it is not a problem for Stoic ethics that it is compatible with a number of metaphysical views is that it is still not compatible with all possible metaphysical views. In philosophical jargon, ethics is underdetermined by metaphysics, but the two are not wholly disconnected. Which means that studying metaphysics is going to be necessary, but not sufficient, to a good understanding of ethics.

So, what sort of metaphysics would be incompatible with Stoic ethics? Here I’m going to direct the reader to an essay that I published recently on my other blog, Footnotes to Plato. That post had to do with something entirely unrelated to the current subject matter, i.e., the metaphysics of the wave function, a fundamental concept in quantum mechanics, and therefore in contemporary physics.

That post, however, is relevant here because it comments on a talk given by Nina Emory, of Brown University, at CUNY’s Graduate Center, and which I attended. In that talk Nina discussed a number of what she called “radical” metaphysical hypotheses which, she contended, are irreconcilable with modern science, meaning that if they were true, then modern science would have gotten something dramatically wrong about how the world works. Nina didn’t suggest that the radical metaphysical hypotheses are incorrect (though I suspect she doesn’t believe them, and neither do I), she only pointed out their prima facie incompatibility with science, which presents a stark choice to the reader: either accept modern scientific findings and implicitly reject the radical metaphysical hypotheses, or accept the latter and implicitly reject modern science.

These are the radical hypotheses in question:

* Solipsistic idealism, the notion that I don’t have a physical body and brain, and that all that exists is my mental states.

* Brain-in-a-vat hypothesis. My brain is floating in a vat, receiving sensorial inputs indirectly. The physical world is nothing like what it appears to be.

* Bostrom simulation hypothesis. The physical universe is nothing like physics describes it, it is, rather, a simulation in someone else’s computer.

* Boltzmann brain hypothesis. My brain formed spontaneously in an empty region of space, as a result of a number of coincidences. Again, the physical universe is nothing like what it appears to be.

I want to suggest here that if any of the radical metaphysical hypotheses above were indeed true, then Stoic ethics would go out the window, thus showing that metaphysics — understood as part of Stoic physics — is indeed relevant to ethics.

What all the above hypotheses have in common is the postulation of a deep nature of the universe that is substantially different from the one we currently accept (as well as from the one that the ancient Stoics accepted). Moreover, two out of four of these (solipsistic idealism and Boltzamann brain) present a solipsistic-idealist scenario (there is only us in the world, and everything is made of thought); one (brain-in-a-vat) acknowledges the existence of some kind of physical world, but tells us that it is radically not the one we think we live in; and the remaining one (Bostrom’s simulation hypothesis) is arguably even worse than solipsism, since it postulates that we don’t really exist, in any sense of “existence” that we are familiar with.

From the Stoic perspective, the four radical metaphysical hypotheses have in common that they deny that human beings are social animals capable of reason. We are either not beings at all, or we are not social, even though presumably we are still capable (somehow) of rationality. Thus “living according to nature” either becomes impossible, or it means something completely different from Stoic canonical interpretation, since we are fundamentally mistaken about what human nature actually is.

What we are left with, then, is the conclusion that some metaphysical hypotheses (e.g., there is a god, and it is immanent in the world; or there is no god at all) are compatible with Stoic ethics, while other hypotheses (e.g., we live in a simulation, or we and the world are pure mental states) are not. That’s all one needs in order to recover the ancient Stoic notion that studying physics (and logic!) is indeed useful to making progress in ethics.

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