Monday, November 1, 2021

Determinism and thought

Occasionally, people have thought that one can refute determinism as follows:

  1. If determinism is true, then all our thinking is determined.

  2. If our thinking is determined, then it is irrational to trust its conclusions.

  3. It is not irrational to trust the conclusions of our thinking.

  4. So, determinism is not true.

But now notice that, plausibly, even if we have indeterministic free will, other animals don’t. And yet it seems at least as reasonable to trust a dog’s epistemic judgment—say, as to the presence of an intruder—as a human’s. Nor would learning that a dog’s thinking is determined or not determined make any difference to our trust in its reliability.

One might respond that things are different in a first-person case. But I don’t see why.


William said...

You may trust a dog in a specific situation, but this does not mean that the animal will not behave in-deterministically in another situation. Whether this means the animal has free will is another issue altogether. The humorous Harvard Law of Animal Behavior is: “Under carefully controlled experimental circumstances, an animal will behave as it damned well pleases.”

Mikhail said...

Doesn't this apply to computers as well? We can trust a computer's output even if its outputs are fully determined.

William said...

Mikhail, I can put a strap of bells on the doorknob to tell me an intruder has moved the door, no thought by the bells involved! The same in a far more complex way with a computer. Our designed artifacts can be deterministic without them having determinism of any of their own thoughts.

I think the dog can create the OP issue due to our intuitions and assumptions coming into conflict. One might feel that the dog consciously thinks about its environment yet still assume that the dog does so in some kind of deterministic fashion. (I have sympathy with the idea that the dog has some kind of consciousness, but mostly disagree about the determinism).

jqb said...

2 is a non sequitur--whether it is rational to trust the conclusions of our thinking depends on whether our thinking is sound, not on whether it is determined.

As for 3 ... sez who? It's clearly nor rational to trust the conclusions of the thinking of whoever came up with this syllogism. Or if it is, then it's not rational to trust the conclusions of my thinking. (And I already know that's not rational, for other reasons.)

But then, what does it actually mean to be rational?

jqb said...

"I can put a strap of bells on the doorknob to tell me an intruder has moved the door, no thought by the bells involved! The same in a far more complex way with a computer"

Only if "same" and "far more complex" can be stretched to hold anything one wants.

"Our designed artifacts can be deterministic without them having determinism of any of their own thoughts."

This is either amphibole or I have no idea what it means. In any case, so what? This is at best a fallacy of denial of the antecedent. The fact is that it's rational to trust the output of a computer's cognitive processing despite it being deterministic (which it isn't necessarily, as it can be randomized), therefore a process being deterministic is clearly not a bar to it being trustable.

Wesley C. said...

@Alex Pruss,

I think 2 would be the most contested premise here. Why assume that determinism is incompatible with a process being rationally sound? Couldn't one just say that our thinking is determined to be rational and thus trustworthy? Especially if one holds that our intellect by nature necessarily grasps necessary truths and can't doubt them, so that deductive conclusions and reasoning are always accepted as valid or even sound? Aquinas himself seems to have thought this as well about how our intellects work.

Heck, one could hold our minds are immaterial yet are determined to be rational since they by nature are directed towards truth and must believe what they clearly perceive to be true.

Alexander R Pruss said...


That all sounds quite reasonable. But some people have felt that (2) is true. I don't get it.

James Reilly said...

But surely the dog's response to an intruder is a clear case where deterministic cause-and-effect would be reliable. The dog is simply responding to stimuli; an intruder enters, the dog hears, smells, or sees something, and responds accordingly. This seems relevantly different from the sort of abstract reasoning that takes place when we think about philosophy. We can reasonably expect a purely deterministic mechanism to reliably tell us about our immediate physical environments; the question is whether we can trust it to guide us to a true philosophical view. It seems like this mechanism (if indeed it is a deterministic mechanism) would be far less reliable than our ordinary senses, since it so often leads us astray (think of all the philosophical issues on which there is no strong consensus).

Wesley C. said...

@James Reilly, I'd question though whether the dog's response is just a preprogrammed response to stimuli. There's most likely more to sensation than mere instinct, insofar as dogs don't just respond automatically but have conscious intentions about what they are doing, and have a flexible memory and imagination that can combine different things in novel way.

Even Aquinas talks about animals as being free in a limited sense, insofar as they aren't determined by nature for one option over another, but their judgment is still determined. And if we accept that freedom / indeterminism can exist even in purely material beings (after all, God is free, and so creation can reflect that in various ways), we could affirm some level of indeterminism even for animals, all the while keeping the distinction between humans and other animals.

James Reilly said...

@Wesley C, If you want to argue that the dog itself has libertarian free will, that's fine by me. I was simply pointing out that, even on the assumption that the dog's actions are purely determined, this doesn't give us good reason to suppose that our own thoughts would be reliable (assuming they too were determined). This is because the deterministic mechanism that produces them (if indeed it is such a mechanism) would be very unreliable.

Consider cases of philosophical disagreement, for example. If determinism is true, then presumably all philosophers' thoughts are guided by the same deterministic process. However, this process leads them to wildly disparate conclusions, such that there are many issues on which no one position has a majority (see the recent PhilSurvey for evidence of this). That seems to be to indicate that this deterministic process, if it exists, is highly unreliable.

Ibrahim Dagher said...

Dr. Pruss,

I've long grappled with these types of arguments. I've argued in print that the better way to think of these arguments is to actually construe them as conditional probabilities, just like Plantinga's EAAN. So, suppose that R is something like 'my cognitive faculties are rationally efficacious'. In general, this is a pretty well accepted epistemic principle:
If some belief B is such that the P(R | B) is one I ought to remain agnostic about, then B is rationally unaffirmable.

Now suppose D is the deterministic thesis (or even weaker, the thesis that our cognitive thinking is a deterministic process). What is the P(R | D)? There are some interesting arguments that we ought to at least reserve judgement about the probability of our faculties being efficacious if we are indeed deterministic agents. I am hesitant, though, as to whether these arguments are decisive. But I do think that is the best way to construe these arguments.
The simplest way to deal with the dog-objection is just to say that the relevant conditional probability statement is not one we need to reserve judgement about.

Alexander R Pruss said...


The philosophical disagreement issue is interesting in this context. On the face of it, I don't see how adding indeterminism, though, makes the philosophical process look any more reliable.

Perhaps, though, you're thinking something like this: If we have indeterministic free will, then some of the disagreement can be attributed to people making morally bad choices (e.g., trying to find ways out of moral obligations) rather than following the philosophical process, and so we have some hope that the philosophical process is reliable.

But that could be said just as much on a deterministic picture, except there the morally bad choices are determined.

Alexander R Pruss said...

This is a good way to look at it. But I don't see reason to say anything about P(R|D) differently from what I'd say about P(R|not-D). My intuition makes them either equal or both indiscernible.