Classical Later Antiquity Islamic World
As of today you can hear an interview with me about Avicenna's flying man thought experiment, on the podcast series Philosophy Bites.
A very interesting podcast. I wonder what kind of cognitive equipment the flying man would have to possess in order to be capable of knowing anything at all - especially something as philosophically abstract as knowing that he exists as a thinking entity. I imagine some philosophers would insist that the man would have to know a language in order to think such thoughts. Has God hard-wired the flying man with language? Can you hard-wire a flying man to possess something like language without his having the impression that an external world exists? And if the flying man is completely devoid of the experience of entities coming into existence, persisting, disappearing, etc. how would it ever occur to him to think about his own existence? It may wind up that the flying man will have to be understood as being a Putnam-style brain in a vat. Avicenna would then say the man falsely *thinks* he knows all kinds of things, but there is only one thing he actually does know, i.e., that he himself exists as a thinking entity. However, if he had never incorrectly thought he *knew* all those things, he would never be able to correctly deduce his own existence...
Thanks, that's a very interesting response. I agree many philosophers nowadays would say that you can't think without language. I'm not sure I agree with that -- Avicenna certainly wouldn't. He would say that God and the celestial intellects think without using language, and in general ancient and medieval followers of Aristotle (which Avicenna is, sort of) believed that language was only an outer expression of inner thought, which was not necessarily considered to be simply mentally rehearsed (natural) language. Also Avicenna draws on the Neoplatonic tradition which recognizes the possibility of "non-discursive" thought, which he also accepts.
Anyway I think what you are saying amounts to denying the basic intuition that someone will indeed be able to think of their own existence (i.e. have a perhaps non-verbal thought equivalent to "gosh, here I am" -- obviously he doesn't need to say to himself explicitly but silently, "I know that I exist") without some other experiences. As I say in the podcast, if you don't share the intuition that he would have such a thought, then the thought experiment probably won't do much for you.
"I think what you are saying amounts to denying the basic intuition that someone will indeed be able to think of their own existence....without some other experiences."
I didn't mean to completely dismiss the "flying man." The flying man does not necessarily require *genuine* sensory experiences in order to have the cognitive capacity to know he exists. It may be sufficient for him to be instantaneously created fully equipped with false memories of pseudo-experiences! Avicenna already assumes that the flying man is created with a fully-developed adult human intelligence; I don't see why (for the purposes of this particular argument) it should bother him if built-in false memories are part of that cognitive equipment.
The reason it would bother him is that the whole point is to isolate the flying man from sensory input; the idea is to persuade you that you don't need sensory input, or memories of sensory input (whether true or false memories) to know you exist. It might be that one could imagine a _different_ thought experiment that involves false memories, as you suggested with Putnam's brains in vats. But that would be aimed at showing something else than what Avicenna is after, such as a skeptical point about our own currentexperiences and memories.
I very much enjoyed your fascinating, thought provoking discussion about Avicenna's flying man thought experiment (so much that I’ve listened to it 3 times). I think you are right that it might help a physicalist appreciate why some intuit not only that some part of us or even our essence is immaterial but that there is a "parallel between the self and God."
I appreciated your explanation of why Avicenna’s use of the flying man thought experiment to argue that the flying man’s self or soul isn’t a body fails, “at least at the very last inference,” as you put it, via your allusion to the identity of water and H2O and the fact that not being aware of an identity does not mean there is none. (I’m reminded of David Papineau’s use of the identity between actor Tony Curtis and Bernie Schwartz, the former being the stage name of the latter, in his arguments in defense of mind-brain identity and physicalism in general.)
What a great site you’ve created here, what a gift! Thank you!
hi prof. Adamson,
I'm not entirely convinced by the 'masked-man fallacy' objection to Avicenna's thought experiment. this is because it seems to me that the kind of awareness that Avicenna is trying to get at with the Flying Man - primitive self-awareness - is just so qualitatively distinct from the kind of awareness that one may have of objects external to the self (e.g., water) that it allows his deduction to go through. self-awareness of that sort is not a part with awareness of objects external to oneself.
what do you think? thanks in advance.
Yes, I'd agree that that is probably what he is after. The difficulty is to say more rigorously what it is about awareness of self that rules out masked man issues (why exactly couldn't one be, as you say, "primitively" aware of the self and yet not know that the self is a physical object?). But the biggest problem is simply that in the text, the explicit premise Avicenna gives is along the lines of "if I am aware of X and not of Y, then X is not identical to Y" which looks like it is exactly making the masked man mistake.
Thanks for listening and writing in!