👤ColinWright🕑13y🔼166🗨️76

(Replying to PARENT post)

As an aside, if you look at the photo credit on that great color photo of Einstein and Gödel, it was snapped by Oskar Morgenstern, one of the fathers of game theory.

http://en.wikipedia.org/wiki/Oskar_Morgenstern

Morgenstern and Einstein were Gödel's closest friends, I've just now learned. It gives me goosebumps looking at that photo and imagining the three of them on that lawn.

Semi-related, here's an account of Gödel's "pent-up lecture" about the inconsistencies in the American constitution that he told to his citizenship examiner: http://morgenstern.jeffreykegler.com/

👤jaysonelliot🕑13y🔼0🗨️0

(Replying to PARENT post)

When I first became fascinated with incompleteness (following initial coursework in theory of computation), it kind of became my "religion" of sorts for a while. But as many mathematicians lament, the Incompleteness Theorem is one of the most popularly abused proofs of all time - used for non-experts to assert their own half-baked pseudo-philosophy (of course, the same goes for quantum mechanics as well).

These are a few books I recommend:

"Incompleteness - The proof and paradox of Kurt Gödel" by Rebecca Goldstein

"Gödel's Proof" by Ernst Nagel (it's a tiny book, not too technical, but technical enough for anyone with a solid CS background to appreciate and understand)

👤vbtemp🕑13y🔼0🗨️0

(Replying to PARENT post)

👤ColinWright🕑13y🔼0🗨️0

(Replying to PARENT post)

"It's like an ill-designed jigsaw puzzle. No matter how you arrange the pieces, you'll always end up with some that won't fit in the end."

I really don't understand this analogy. The first incompleteness theorem shows that there are statements true of the natural numbers which aren't provable from any sufficiently strong recursive theory. It's more like Th(N) (the set of statements true of the natural numbers) being a jigsaw puzzle from which many pieces will always be missing if you start with a recursive set of pieces and try to lay down only those pieces which a provable from your initial set. Nothing "won't fit": there aren't inconsistencies or incompatibilities at work here, but incompleteness.

👤ionfish🕑13y🔼0🗨️0

(Replying to PARENT post)

On a related note, does anyone know where I would look to understand reducibility of formal systems to one another?

I'm really interested by questions like:

Why is second order logic irreducible to first order logic if I could use first order logic to reason about the behavior of a turing machine running a second order logic theorem prover with whatever inputs I like?

How do I get something that can do what I can do, which is to say take any formal system and prove theorems with it? How do you determine what formal systems are "valid" logics? (Leading to sensible conclusions rather than nonsense like A & ~A)

👤haliax🕑13y🔼0🗨️0

(Replying to PARENT post)

Stephen Hawking «Gödel and the end of physics»

http://www.damtp.cam.ac.uk/events/strings02/dirac/hawking/

👤Fice🕑13y🔼0🗨️0

(Replying to PARENT post)

GEB sits on my nightstand with too little time to be read. It might have to get bumped up the priority queue a bit.
👤SoftwareMaven🕑13y🔼0🗨️0

(Replying to PARENT post)

"Another result that derives from Gödel's ideas is the demonstration that no program that does not alter a computer's operating system can detect all programs that do. In other words, no program can find all the viruses on your computer, unless it interferes with and alters the operating system."

I think I just heard a 'pop'ping sound.. but really, writers try too hard sometimes to make this stuff accessible to people. I don't think someone who is going to get a whole half-way into the article is going to need such reductionism to catch their interest; I'd honestly be more excited if the actual symbolic definition of the theorem was shown to me at that point.

👤ttttannebaum🕑13y🔼0🗨️0

(Replying to PARENT post)

In 1949 he demonstrated that universes in which time travel into the past is possible were compatible with Einstein's equations.

Wait, what?! Anyone have a ref?

Edit: Thanks to andyjohnson and vbtemp. TIA for others too.

👤jpdoctor🕑13y🔼0🗨️0

(Replying to PARENT post)

For people interested in the original from 1931: http://www.w-k-essler.de/pdfs/goedel.pdf (in German). Work of art IMHO.
👤tluyben2🕑13y🔼0🗨️0

(Replying to PARENT post)

While that's biographically interesting, you really don't get off the hook from understanding that he used basically the same approach of Cantor's diagonalization.
👤lcargill99🕑13y🔼0🗨️0

(Replying to PARENT post)

Its always fascinating to read about Gödel. I have not read GEB, yet reading about his findings has really changed the way I think about things.

Thanks for posting this article.

👤rmATinnovafy🕑13y🔼0🗨️0

(Replying to PARENT post)

What I get out of Goedel is this: There are some things that are true that cannot be proved.
👤ChrisHugh🕑13y🔼0🗨️0