A
Anselm33
Guest
“Shadows of the Mind” is more expanded than “The Emperor’s New Mind” (ENM) and it answers critiques raised against the arguments in ENM. In Shadows Penrose has an extended discussion of why mathematical intelligence and insight is a non-computable process, a much more extended discussion than in ENM. The Halting Theorem business is in fact, not his only argument against computable awareness.Well, I’ve not read Shadows of the Mind, but I have read parts of Penrose’s The Emperor’s New Mind, and lots of related discussion online, over the years. I think this bit from Penrose on the subject here is relevant:
This I think clearly locates Penrose’s objection in his understanding of Gödel Incompleteness. He talks later in the article about various criticisms of his take on this, and allows that Daniel Dennett’s “bottom up” argument is one that bears more analysis (which I think an understatement, but a fair one), but the problem is more fundamental, I say: Gödel’s theorem needn’t apply for strong AI, or “computational consciousness”. All computational systems we have now that are formal such that Gödel’s theorem applies still compute, still resolve. Gödel’s insight doesn’t invalidate or change that. Rather, it just notes that the system has transcendental limitations. It’s self-consistency necessarily means it cannot possibly be complete in its expositions, it’s proofs.
That in no way denies strong AI in principle, and if you’ve read Penrose on this, you know that he doesn’t claim is does. He just thinks there’s something “simply non-computable” in consciousness. You don’t need to rely on Gödel for that, and Gödel can’t even help you get there, or show that to be true.
Penrose says this later in the article:
There’s nothing to “get around” to establish the viability of strong AI, per Gödel, that I can see. Any “computable consciousness” would have true propositions that were non-computable, but so does any formal system, and we have plenty of examples where that is no crisis of computation. I’ve read a lot of Penrose, but not all, but from what I gather, he never shows us where the limitation actually obtains. That makes sense, and is fairly obvious, because we don’t have a working, robust model of consciousness yet as a reference point. We don’t even know what we are applying Gödel to, if it is even applicable.
Have I missed the main substantive point from Penrose here?
-TS
Now I won’t deny that digital computing can emulate many aspects of human intelligence, whether from top-down or bottom-up type programming (e.g. for the former, chess-playing and for the latter medical diagnoses of images via neural network training). Nevertheless, if there is only one mathematical procedure that can’t be done computationally IN PRINCIPLE (not because of present day limitations on computing power), then that indicates to me that there are things–concepts, thought processes–that humans can do that computers will not be able to do and that therefore the universe (which includes humans?) can not be computable.
And I’m not necessarily using the argument about formal systems, which Penrose uses to say that humans can do math that a computer will never be able to do.
Here is the specific URL for the polyominoes (taken from Shadows of the Mind):
books.google.com/books?id=gDbOAK89tmcC&pg=PA30&lpg=PA30&dq=non-computable+polyominoes&source=bl&ots=8RIsObpC2O&sig=bMTYGofqh2IukA89kVELecPjavs&hl=en&ei=8BbBTJjHIIX6lwfHmNDYCQ&sa=X&oi=book_result&ct=result&resnum=2&ved=0CBUQ6AEwAQ#v=onepage&q=non-computable%20polyominoes&f=false
Here is the link to non-computable functions:
arxiv.org/abs/math/0406416
and
www-formal.stanford.edu/jmc/basis1/node6.html
and links contained therein.
I should add that I don’t have a dog in this fight with respect to religious belief. I can imagine “that great programmer in the sky” as easily as any Creator God, so my problem with “It from bit” is not a theological one, but the following. I’m trying to see if mentality–mind can be understood on a physical basis. At the moment I’m not sure it can.