Phil 101: Intro to Free Will (Part 2 of 2)

Free Will and Determinism (continued)

We left off last time talking about how to understand “Determinism” and whether to believe it’s true.

We said that our best theories nowadays of quantum physics are not obviously deterministic. They don’t say “in situations like this, so-and-so is guaranteed to happen.” Instead they involve probabilities in ways we can’t eliminate. However, it is philosophically controversial how the probabilities in those theories should be interpreted. Hence, one cannot easily say whether or not our best theories of quantum physics posit that our world has indeterministic laws.

To show that our laws of nature are indeterministic, one needs to show that the probabilities our physical theories appeal to are objective probabilities. But that is philosophically controversial. It is controversial whether the probabilities that appear in our theories of quantum physics should be understood as epistemic probabilities or objective probabilities.

If you want to read more on debates about how to interpret the probabilities in quantum physics, my friends who are experts on those issues say that this book is an excellent introduction and history of the debate.

Even if you think Causal Determinism is false about our world, still, you will learn a lot about our concept of free will by investigating what would follow if Causal Determinism were true.

Some philosophers hold the view that Determinism and free will are incompatible with each other. They think that if you’ve got one, you can’t have the other. We call these philosophers Incompatibilists. Other philosophers think that Determinism and free will are compatible. They think that it’s possible to have both. We call these philosophers Compatibilists. We can further sub-divide the Incompatibilists and the Compatibilists as follows:

Can't have both free will and Determinism


We have free will
So Determinism is false (Libertarians)
We lack free will
Perhaps because
Determinism is true (Hard Determinists),
or perhaps we lack it even though Determinism is false
Can have both free will and Determinism


Soft Determinists
Determinism is true and we have free will

In a large poll of philosophers in 2020, 17% of the respondents favored Libertarianism, 15% favored us having no free will (so altogether, 32% were Incompatibilists), and 56% favored Compatibilism. (The remaining 12% were undecided, thought the question was too unclear, or that there’s no fact of the matter, and so on.) Philosophy isn’t a popularity contest, so these numbers don’t tell us which view is right. But they do show how much controversy there is, and that each of these positions has some serious support.

Is determinism incompatible with freedom?

Does determinism imply — if it were true, which we’re not presupposing — that you can only choose and do the things you actually choose and do?

The answer will depend a lot on what we mean by “choosing” something, and by “doing” something, and most especially, by the word “can.” We spent a chunk of the class starting to get a feel for why it might not be straightforward what we mean by “can.”

Different senses of “mother”

I talked about an example where Baby X had a complicated backstory. The egg that was fertilized and grew into Baby X came from one woman, A. But then that fertilized egg was implanted in the uterus of a second woman, B, who actually gave birth to Baby X. Then Baby X was immediately adopted and raised by a lesbian couple, C and D.

Now suppose someone asks, Who is Baby X’s mother? Or, how many mothers did Baby X have? We’re going to want to distinguish different senses of “mother,” aren’t we? Someone in the chat said we could call A the “biological mother,” B the “birth mother,” and C and D the “adoptive mothers.” Our one word “mother” really covers a range of different relations someone can stand in. In many cases a single woman stands in all of these relations, but in other cases not. You might want to say that Baby X has “four mothers.” If you do say that, though, be careful. C and D are both Baby X’s mother in the same sense. You can say that A is also Baby X’s mother, but it’s not in the same sense that C and D are. A is Baby X’s mother in a different sense than C and D are.

Another twist I put on this story was to imagine some guy George who says that mother means “female caregiver who spends the most time with you.” That might sound somewhat plausible at first — at least, at capturing one of our different notions of motherhood. But then if you think about it more, you realize that George’s proposal might have the consequence that it’s not C and D who are Baby X’s mother, but rather Baby X’s nanny. (I imagine that C and D have busy jobs and so spend less time with the baby than the nanny does.) And that doesn’t seem to be the right result. We wouldn’t call the nanny the mother. If the doctor’s office says this form needs to be signed by the baby’s mother (or any parent), the nanny’s signature wouldn’t be enough. So George’s proposal doesn’t seem quite right. It’s not easy or straightforward to say what makes it the case that C and D are Baby X’s mothers and the nanny is not. Presumably it has something to do with legal conventions. But even if we’re not able yet to put our finger on what explains why C and D count as mothers but the nanny doesn’t, we ought to have enough understanding of how we use the concept of mother to see that it would be wrong to count the nanny as Baby X’s mother (or even one of Baby X’s mothers). Since George’s proposal would count the nanny as a mother, George’s proposal is incorrect.

Now the reason I introduced George and his incorrect proposal is to distinguish between the way that there are different senses of “mother” where, as we really do understand that notion, A counts as mother in one sense, and C and D in another sense, and so on. On the other hand, although we might say things like “The nanny is only a mother in George’s sense,” George’s sense of “mother” isn’t a fourth sense of mother in the same way as the earlier senses are. It’s a proposal about what “mother” means, as it turns out an incorrect proposal. We’ll need to pay attention to when we’re talking about senses of a concept that we really do already understand and recognize, and when we’re talking about mere proposals, where it’s up for debate whether that really captures any of our concepts. George’s sense of “mother” is just a proposal. It’s not a sense of “mother” that anyone (apart from maybe George, if he talks himself into it) really understands that concept to have.

This is going to come up in our discussions of free will. We’re going to see various proposals that philosophers make about what words like “can” and “free” mean. We might find ourselves talking about “can in Philosopher Z’s sense.” But it’ll be up for debate whether this is anything anyone ordinarily means by “can.”

Can you dream whatever you want?

In class I presented what was supposed to be a deliberately provocative argument that everyone should always have amazing blissful dreams, and if they don’t it’s their own fault. The argument went something like this: In a dream, anything can happen. You can get swallowed by a whale; you can turn into a dragon; you can get served your favorite meal on an amethyst platter. Just about anything you might want to happen can happen in a dream. So, since you can get anything you want in a dream — there’s no obstacle to it — why don’t you? It’s your own dumb fault if you don’t. Everybody should always have the most satisfying excellent dreams, and if they don’t, they only have themselves to blame.

In our class discussion, some interesting points came out.

What I was trying to bring out with the argument was a sneaky move. In the early part of the argument, I talk about what “can happen,” meaning this is possible, that’s a way dreams can turn out. But in the later part of the argument, when I say “you can get whatever you want,” why don’t you, there’s no obstacle — there “can” is about you having the choice, and you being able to decide what happens. And just because a dream is in some sense possible doesn’t mean that you have the choice, and you can decide what happens. Maybe somebody else decides, or nobody decides, it’s just random. It’s not up to you. It’d still be true, in the original sense, that anything can happen.

So what this argument is supposed to illustrate is that “can” is a slippery word, and it might mean different things when we use it in different places. It’s not always obvious what exactly its meaning is. This is something we have to pay attention to.

More examples of “can” meaning different things

Consider the following claims.

  1. Felix can lift weights, but he’s an ex-felon so he can’t vote.
  2. I can’t lift any weights today, I have meetings from dawn to dusk.
  3. John can already lift 150 pounds, and I think he can lift 200 too — he just needs some extra training.

These examples show the word “can” (and “can’t”) being used in a variety of ways. In (1) we’re talking about what Felix is permitted to do. In (2) we’re talking about what I have the opportunity to do. In (3) we’re talking about what John now has strength enough to do, and speculating about what strength is achievable for him, with a small-to-moderate amount of extra training.

It’s not an easy matter to identify and articulate what the various senses of “can” used in these examples come to. But I hope it is intuitively clear that the sense in which 1. is saying Felix can’t vote is not the same as the sense in which 2. is saying the speaker can’t lift weights, and so on. Claims of the form “X can do such-and-such” mean a variety of different things. So too with claims like form “It could have happened that Y” and “X can bring it about that Y.” There is not just one way to interpret such claims.

Back to Determinism

Now let’s go back to Determinism.

We were asking whether, if Determinism is true, people can only choose and do the single things they in fact choose and do. Now that we’re alerted to the multiplicity of things “can” can mean, we have to ask: can only do that, in what sense of “can”?

Is there some sense of “can” according to which Determinism entails that you can only do the things you in fact do? Perhaps. There may be senses of “can” where that follows. If Determinism is true, then, given the way the world was before you were born, it was causally settled that you would do the things you in fact do. You “can’t” do anything else — in the sense that, given the way the past is, the laws of nature exclude your doing anything else. So in that sense of “can,” the things you in fact do are the only things you can do.

But the words “can” (and “could” and “able” and so on) can mean many different things. What we need to know is not whether there’s a sense of “can” according to which Determinism entails that you can only do the things you in fact do. Perhaps there are other senses of “can” that do not have that consequence. What we need to know is not whether there’s some sense of “can” which lets us say such-and-such, or some sense of “can” which lets us say something else. Our task is much harder than that. What we need to do is to somehow identify senses of “can” that we’re independently interested in, and ask whether, with that sense of “can,” Determinism entails that you can only do the things you in fact do. For example, we might think that being morally responsible for an act entails that you can refrain from performing that act. Is the sense of “can” involved in that thought compatible with Determinism? This question is not very easy to answer.