It’s worse than I thought. Aaronson really does want to address the free will debate in philosophy—and utterly botches the job.
Aaronson speaks for some of his interlocutors (who are very smart—i.e. they say what I would say ;) ):
Suppose that only “ordinary” quantum randomness and classical chaos turned out to be involved: how on earth could that matter, outside the narrow confines of free-will debates? Is the variety of free will that apparently interests you—one based on the physical unpredictability of our choices—really a variety “worth wanting,” in Daniel Dennett’s famous phrase [27]?
and answers:
As a first remark, if there’s anything in this debate that all sides can agree on, hopefully they can agree that the truth (whatever it is) doesn’t care what we want, consider “worth wanting,” or think is necessary or sufficient to make our lives meaningful!
Uh, so: the truth about the modal number of hairs on a human foot, for example, doesn’t care what we want. But, if I were to claim that (a good portion of) a famous philosophical debate amounted to the question of how many hairs are on our feet, you could reject the claim immediately. And you could cite the fact that nobody gives a damn about that as a sufficient reason to reject the substitution of the new question for the old. Sure, in this toy example, you could cite many other reasons too. But with philosophical (using the next word super broadly) definitions, sometimes the most obvious flaw is that nobody gives a damn about the definiens, while lots care passionately about the concept supposedly defined. Dennett rightly nails much philosophizing about free will, on precisely this point.
Interlocutors:
But if the event is undetermined, it isn’t “free” either: it’s merely arbitrary, capricious, and random.
Aaronson:
An event can be “arbitrary,” in the sense of being undetermined by previous events, without being random in the narrower technical sense of being generated by some known or knowable probabilistic process.
But this doesn’t address the point, unless Knightian-uncertain “actions” somehow fall more under the control of the agent than do probabilistic processes. The truth is the opposite. I have the most control over actions that flow deterministically from my beliefs and desires. I have almost as much, if it is highly probable that my act will be the one that the beliefs and desires indicate is best. And I have none, if it is completely uncertain. For example, if I am pondering whether to eat a berry and then realize that this type of berry is fatally poisonous, this realization should ideally be decisive, with certainty. But I’ll settle for 99.99...% probability that I don’t eat it. If it is wide-open uncertain whether I will eat it—arbitrary in a deep way—that does not help my sense of control and agency. To put it mildly!
Finally, Aaronson has a close brush with the truth when he rejects the following premise of the Consequence Argument (section 2.9):
(ii) The state of the universe 100 million years ago is clearly outside our ability to alter.
Aaronson replies:
there might be many possible settings of the past microfacts—the polarizations of individual photons, etc. [...] our choices today might play a role in selecting one past from a giant ensemble of macroscopically-identical but microscopically-different pasts.
Only one microscopic past is consistent with our choice today. But the same can be said of the whole past on a classically-determinist scientific picture. As Carl Hoefer says in the Stanford Encyclopedia
they can be viewed as bi-directionally deterministic. That is, a specification of the state of the world at a time t, along with the laws, determines not only how things go after t, but also how things go before t. Philosophers, while not exactly unaware of this symmetry, tend to ignore it when thinking of the bearing of determinism on the free will issue.
And that’s a mistake, as Hoefer indicates in his conclusion. The physics of deterministic theories (and also, I would add, any probabilistic quantum theory that gives sufficient probabilistic weight to our beliefs, desires, and reasoning in producing action) supports strong compatibilism, not Aaronson’s weak version.
I agree with you on unpredictability not being important for agency, but I don’t understand the last third of this comment. What is the point that you are trying to make about bi-directional determinism? Specifically, could you restate the mistake you think Aaronson is making in the “our choices today might play a role” quote?
Sorry, I was unclear. I don’t think that’s a mistake at all! The only “problem” is that it may be an understatement. On a bi-directional determinist picture, our choices today utterly decisively select one past, in a logical sense. That is, statements specifically describing a single past follow logically from statements describing our choices today plus other facts of today’s universe. The present still doesn’t cause the past, but that’s a mere tautology: we call the later event the “effect” and the earlier one the “cause”.
our choices today utterly decisively select one past, in a logical sense
That’s not necessarily true if multiple pasts are consistent with the state of the present, right? In other words, if there is information loss as you move forward in time.
Indeed. Those wouldn’t be bi-directional determinist theories, though. Interestingly, QM gets portrayed a lot like a bi-directional determinist theory in the wiki article on the black hole information paradox. (I don’t know enough QM to know how accurate that is.)
It’s worse than I thought. Aaronson really does want to address the free will debate in philosophy—and utterly botches the job.
Aaronson speaks for some of his interlocutors (who are very smart—i.e. they say what I would say ;) ):
and answers:
Uh, so: the truth about the modal number of hairs on a human foot, for example, doesn’t care what we want. But, if I were to claim that (a good portion of) a famous philosophical debate amounted to the question of how many hairs are on our feet, you could reject the claim immediately. And you could cite the fact that nobody gives a damn about that as a sufficient reason to reject the substitution of the new question for the old. Sure, in this toy example, you could cite many other reasons too. But with philosophical (using the next word super broadly) definitions, sometimes the most obvious flaw is that nobody gives a damn about the definiens, while lots care passionately about the concept supposedly defined. Dennett rightly nails much philosophizing about free will, on precisely this point.
Interlocutors:
Aaronson:
But this doesn’t address the point, unless Knightian-uncertain “actions” somehow fall more under the control of the agent than do probabilistic processes. The truth is the opposite. I have the most control over actions that flow deterministically from my beliefs and desires. I have almost as much, if it is highly probable that my act will be the one that the beliefs and desires indicate is best. And I have none, if it is completely uncertain. For example, if I am pondering whether to eat a berry and then realize that this type of berry is fatally poisonous, this realization should ideally be decisive, with certainty. But I’ll settle for 99.99...% probability that I don’t eat it. If it is wide-open uncertain whether I will eat it—arbitrary in a deep way—that does not help my sense of control and agency. To put it mildly!
Finally, Aaronson has a close brush with the truth when he rejects the following premise of the Consequence Argument (section 2.9):
Aaronson replies:
Only one microscopic past is consistent with our choice today. But the same can be said of the whole past on a classically-determinist scientific picture. As Carl Hoefer says in the Stanford Encyclopedia
And that’s a mistake, as Hoefer indicates in his conclusion. The physics of deterministic theories (and also, I would add, any probabilistic quantum theory that gives sufficient probabilistic weight to our beliefs, desires, and reasoning in producing action) supports strong compatibilism, not Aaronson’s weak version.
Missed it by (fingers close together) that much!
I agree with you on unpredictability not being important for agency, but I don’t understand the last third of this comment. What is the point that you are trying to make about bi-directional determinism? Specifically, could you restate the mistake you think Aaronson is making in the “our choices today might play a role” quote?
Sorry, I was unclear. I don’t think that’s a mistake at all! The only “problem” is that it may be an understatement. On a bi-directional determinist picture, our choices today utterly decisively select one past, in a logical sense. That is, statements specifically describing a single past follow logically from statements describing our choices today plus other facts of today’s universe. The present still doesn’t cause the past, but that’s a mere tautology: we call the later event the “effect” and the earlier one the “cause”.
That’s not necessarily true if multiple pasts are consistent with the state of the present, right? In other words, if there is information loss as you move forward in time.
Indeed. Those wouldn’t be bi-directional determinist theories, though. Interestingly, QM gets portrayed a lot like a bi-directional determinist theory in the wiki article on the black hole information paradox. (I don’t know enough QM to know how accurate that is.)