Harvey asked:

Is there free will?

Answer by Massimo Pigliucci

It very much depends on what one means by ‘free will.’ I don’t actually like the term ‘free will’ at all. It traces back to a theological concept of contra-causal (i.e., independent of any cause) ability to make decisions, which supposedly is the get-out-of-jail-free card available to theologians who are embarrassed by the problem of evil and how to reconcile it with the alleged existence of an all-powerful and all-good god. I’m a scientist and naturalist philosopher, so I think the idea of contra-causal anything is just plain silly. I think that a much better way to talk about the subject at hand is by using the preferred term among cognitive scientists: volition, i.e. the ability of human beings (and possibly other animals) to make autonomous (not contra-causal!) decisions exercising their agency.

Either way, classically there are three fundamental ways to think about free will/ volition from a philosophical perspective: compatibilism, deterministic incompatibilism, and libertarian incompatibilism. Each comes in a variety of flavors, but we’ll stick to the fundamentals. Beginning with the second one, deterministic incompatibilism is the idea that — since the universe is deterministic (meaning, it behaves according to the laws of physics, without exceptions) — then humans are not ‘free’ to do anything at all. We have the mistaken impression that we make autonomous decisions, but that’s just an illusion. There are neither free lunches nor free will.

Libertarian incompatibilism has nothing to do with the political meaning (in the US especially) of the term ‘libertarianism.’ Rather, it affirms our sense that we are agents capable of autonomous decision making, and concludes that if this is incompatible with determinism, so much the worse for determinism. (As it turns out, though, even if the laws of nature were irreducibly stochastic — as in some interpretations of quantum mechanics — one still couldn’t have free will independently of such laws). Relatively few philosophers, and even fewer scientists, hold to this bold position, because it seems to flatly contradict much of what we have learned from science about how the world works.

Which leaves us with compatibilism. This is the idea that we can have our cake and eat it too, in a sense. Compatibilists accept that the universe is a deterministic system, but they also agree that human beings are agents with the ability of making their own decisions. How is this possible? Think of your brain, at the least in part, as a type of evolved biological machinery to make good enough decisions about your survival and reproduction. A functional human brain makes better decisions than a less functional one (e.g., compulsive gamblers, or people with different types of severe neurological damage). It also makes better decisions than the less sophisticated brains of other species, largely because we seem to be unique (on this planet) in our ability — under ideal circumstances — to reflect on the available options before actually taking a particular course of action.

In recent years I have been developing a fourth position, which you won’t find in philosophy textbooks, but here it is anyway. I call it epistemological agnosticism. It basically says that the conclusion that the universe is deterministic is metaphysical in nature, and — currently at the least — not really in line with scientific epistemology, i.e., it cannot actually be confirmed or falsified on the basis of empirical evidence. There are two reasons for this. On the one hand, the most fundamental physical theory we have so far, quantum mechanics, is both incomplete (we know this for a fact) and amenable to either deterministic or stochastic interpretations. So, determinism, contra popular conception, is not a theoretical necessity dictated by fundamental physics, yet.

On the other hand, even if physicists did come up with a fundamental deterministic theory, they still wouldn’t be able to deploy it to contribute anything meaningful to the understanding of a huge range of complex phenomena, from biological to social ones. These phenomena, of course, are compatible with fundamental physics (they better!), but it is an open question whether fundamental physics is all that is needed to explain them.

How could that possibly be? Because it is possible that there are true ’emergent properties,’ i.e., properties of natural systems that manifest themselves only at certain levels of complexity, and which cannot be reduced to lower levels of explanation (again, while being compatible with them). True, or ‘strong,’ emergence is rather unpopular these days among physicists and philosophers, but biologists and other scientists have been considering it for the simple reason that in order to explain the phenomena they are interested in they need to deploy concepts and theories at a much higher level than quantum mechanics (e.g., the theory of evolution, or a number of principles in ecology).

So, on the one hand we have a strong metaphysical claim: the universe is a deterministic system. On the other hand we have the epistemic need to deploy different theories at distinct levels of explanations of sub-systems of that very same universe (like biological organisms, ecosystems, etc.). In other words, at the moment, metaphysically speaking we are making a claim that does not align with our current epistemology. Since I think it is always a good idea to have one’s metaphysics go hand in hand with one’s epistemology, I remain agnostic about true emergence, and therefore about ‘free will’ (because human volition could be yet another example of emergent properties of matter, like phase transitions in solid state physics; or ecosystem functions in ecology). Notice that this is not an argument in favor of emergent properties, but only of their possibility. And it certainly isn’t an argument in favor of contra-causal free will: even if true emergent properties exist, they still govern causal interactions among components of a system, and still represent a type of natural law.