Probably preaching to the choir here, but I don’t understand the conceivability argument for p-zombies. It seems to rely on the idea that human intuitions (at least among smart, philosophically sophisticated people) are a reliable detector of what is and is not logically possible.
But we know from other areas of study (e.g. math) that this is almost certainly false.
Eg, I’m pretty good at math (majored in it in undergrad, performed reasonably well). But unless I’m tracking things carefully, it’s not immediately obvious to me (and certainly not inconceivable) that pi is a rational number. But of course the irrationality of pi is not just an empirical fact but a logical necessity.
Even more straightforwardly, one can easily construct Boolean SAT problems where the answer can conceivably be either True or False to a human eye. But only one of the answers is logically possible! Humans are far from logically omniscient rational actors.
Conceivability is not invoked for logical statements, or mathematical statements about abstract objects. But zombies seem to be concrete rather than abstract objects. Similar to pink elephants. It would be absurd to conjecture that pink elephants are mathematically impossible. (More specifically, both physical and mental objects are typically counted as concrete.) It would also seem strange to assume that elephants being pink is logically impossible. Or things being faster than light. These don’t seem like statements that could hide a logical contradiction.
I think there’s an underlying failure to define what it is that’s logically conceivable. Those math problems have a formal definition of correctness. P-zombies do not—even if there is a compelling argument, we have no clue what the results mean, or how we’d verify them. Which leads to realizing that even if someone says “this is conceivable”, you have no reason to believe they’re conceiving the same thing you mean.
I think you’re objecting to 2. I think you’re using a loose definition of “conceivable,” meaning no contradiction obvious to the speaker. I agree that’s not relevant. The relevant notion of “conceivable” is not conceivable by a particular human but more like conceivable by a super smart ideal person who’s thought about it for a long time and made all possible deductions.
1. doesn’t just follow from some humans’ intuitions: it needs argument.
Sure but then this begs the question since I’ve never met a super smart ideal person who’s thought about it for a long time and made all possible deductions. So then using that definition of “conceivable”, 1) is false (or at least undetermined).
we can make progress by thinking about it and making arguments.
I mean real progress is via proof and things leading up to a proof right? I’m not discounting mathematical intuition here but the ~entirety of the game comes from the correct formalisms/proofs, which is a very different notion of “thinking.”
Put in a different way, mathematics (at least ideally, in the abstract) is ~mind-independent.
Do you think ideal reasoning is well-defined? In the limit I feel like you run into classic problems like anti-induction, daemons, and all sorts of other issues that I assume people outside of our community also think about. Is there a particularly concrete definition philosophers like Chalmers use?
Those considerations aside, the main way in which conceivability arguments can go wrong is by subtle conceptual confusion: if we are insufficiently reflective we can overlook an incoherence in a purported possibility, by taking a conceived-of situation and misdescribing it. For example, one might think that one can conceive of a situation in which Fermat’s last theorem is false, by imagining a situation in which leading mathematicians declare that they have found a counterexample. But given that the theorem is actually true, this situation is being misdescribed: it is really a scenario in which Fermat’s last theorem is true, and in which some mathematicians make a mistake. Importantly, though, this kind of mistake always lies in the a priori domain, as it arises from the incorrect application of the primary intensions of our concepts to a conceived situation. Sufficient reflection will reveal that the concepts are being incorrectly applied, and that the claim of logical possibility is not justified.
So the only route available to an opponent here is to claim that in describing the zombie world as a zombie world, we are misapplying the concepts, and that in fact there is a conceptual contradiction lurking in the description. Perhaps if we thought about it clearly enough we would realize that by imagining a physically identical world we are thereby automatically imagining a world in which there is conscious experience. But then the burden is on the opponent to give us some idea of where the contradiction might lie in the apparently quite coherent description. If no internal incoherence can be revealed, then there is a very strong case that the zombie world is logically possible.
As before, I can detect no internal incoherence; I have a clear picture of what I am conceiving when I conceive of a zombie. Still, some people find conceivability arguments difficult to adjudicate, particularly where strange ideas such as this one are concerned. It is therefore fortunate that every point made using zombies can also be made in other ways, for example by considering epistemology and analysis. To many, arguments of the latter sort (such as arguments 3-5 below) are more straightforward and therefore make a stronger foundation in the argument against logical supervenience. But zombies at least provide a vivid illustration of important issues in the vicinity.
(II.7, “Argument 1: The logical possibility of zombies”. Pg. 98).
Probably preaching to the choir here, but I don’t understand the conceivability argument for p-zombies. It seems to rely on the idea that human intuitions (at least among smart, philosophically sophisticated people) are a reliable detector of what is and is not logically possible.
But we know from other areas of study (e.g. math) that this is almost certainly false.
Eg, I’m pretty good at math (majored in it in undergrad, performed reasonably well). But unless I’m tracking things carefully, it’s not immediately obvious to me (and certainly not inconceivable) that pi is a rational number. But of course the irrationality of pi is not just an empirical fact but a logical necessity.
Even more straightforwardly, one can easily construct Boolean SAT problems where the answer can conceivably be either True or False to a human eye. But only one of the answers is logically possible! Humans are far from logically omniscient rational actors.
Conceivability is not invoked for logical statements, or mathematical statements about abstract objects. But zombies seem to be concrete rather than abstract objects. Similar to pink elephants. It would be absurd to conjecture that pink elephants are mathematically impossible. (More specifically, both physical and mental objects are typically counted as concrete.) It would also seem strange to assume that elephants being pink is logically impossible. Or things being faster than light. These don’t seem like statements that could hide a logical contradiction.
Sure, I agree about the pink elephants. I’m less sure about the speed of light.
I think there’s an underlying failure to define what it is that’s logically conceivable. Those math problems have a formal definition of correctness. P-zombies do not—even if there is a compelling argument, we have no clue what the results mean, or how we’d verify them. Which leads to realizing that even if someone says “this is conceivable”, you have no reason to believe they’re conceiving the same thing you mean.
I think the argument is
I think you’re objecting to 2. I think you’re using a loose definition of “conceivable,” meaning no contradiction obvious to the speaker. I agree that’s not relevant. The relevant notion of “conceivable” is not conceivable by a particular human but more like conceivable by a super smart ideal person who’s thought about it for a long time and made all possible deductions.
1. doesn’t just follow from some humans’ intuitions: it needs argument.
Sure but then this begs the question since I’ve never met a super smart ideal person who’s thought about it for a long time and made all possible deductions. So then using that definition of “conceivable”, 1) is false (or at least undetermined).
No, it’s like the irrationality of pi or the Riemann hypothesis: not super obvious and we can make progress by thinking about it and making arguments.
I mean real progress is via proof and things leading up to a proof right? I’m not discounting mathematical intuition here but the ~entirety of the game comes from the correct formalisms/proofs, which is a very different notion of “thinking.”
Put in a different way, mathematics (at least ideally, in the abstract) is ~mind-independent.
Yeah, any relevant notion of conceivability is surely independent of particular minds
Do you think ideal reasoning is well-defined? In the limit I feel like you run into classic problems like anti-induction, daemons, and all sorts of other issues that I assume people outside of our community also think about. Is there a particularly concrete definition philosophers like Chalmers use?
You may find it helpful to read the relevant sections of The Conscious Mind by David Chalmers, the original thorough examination of his view:
(II.7, “Argument 1: The logical possibility of zombies”. Pg. 98).