5 ms·

The Man Who Tried to Redeem the World with Logic

147 points by robgering 12y ago

javajosh 12y ago
Having read _Principia_ did Pitts read Kurt Goedel[1]? I would very much like to know what he thought of it! What an incredibly sad story - burning years of work in meloncholy, all thanks to the lies of an angry woman. Wiener, though, shares a great deal of blame - a man should not pass judgement in on his friends without inquiring into the truth of the matter. [1]https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_...
- dvt 12y ago
  Given that Gödel and Pitts most likely wrote to one another (although their correspondence doesn't survive), it's very probable that they were intimately familiar with the work of one another. There's an entire chapter dedicated to Walter Pitts in Kurt Gödel: Collected Works, Volume V.
- leoc 12y ago
  Anyone so active in formal logic in mid-C20 (or since) could not possibly have missed Gödel's work.
nanis 12y ago
I thought that was Spinoza.
- sowhatquestion 12y ago
  I was going to guess Hegel. Either one would work though
  - vanderZwan 12y ago
    Wasn't Descartes partially motivated by the horrors of the Thirty Years war?
carapace 12y ago
Such a terrible tragedy, both personal and for the world. I highly recommend the book referenced: "Dark Hero of the Information Age: In Search of Norbert Wiener, the Father of Cybernetics". R.I.P. Walter Pitts (One thing that troubles me slightly: this article mentions a possible cause of the break between Wiener and the others which is presented as speculation in the book, if I remember correctly, but stated here as a bald fact. In any event I wish that Wiener hadn't acted so rashly.)
javert 12y ago
Ayn Rand?
- plink 12y ago
  logic, not hubris.
- xmonkee 12y ago
  lol
- psychometry 12y ago
  I thought this was a joke until I read your HN profile. Then I discovered that the joke is much bigger than this solitary comment.
  - dang 12y ago
    Please don't post unduly personal comments on Hacker News.
xmonkee 12y ago
This article is fascinating. I had no idea that the Von Neumann machine was an extrapolation of a mental model. Even more fascinating, that the existince of a symbolic computation machine made the possibility of purely symobolic epistimology impossible. It's like they abstracted a lever higher than they wanted to and then made a cleaner, simpler implementation of it. And now with modern AI we are doubling down on that implementation and trying to build a new kind of intelligence no top of it.
- darkmighty 12y ago
  It's fascinating that we've built a model of a computer, which was impractical; then we've modeled the brain with very high abstraction and then actually built a computer. Now we're back to modelling the brain because while the abstractions are universal they're not efficient enough. We need to nitty gritty details on efficient ways of learning and computing approximately ("probably approximately correct"), quickly and efficiently. Which is what I believe the article tries to convey as the last epiphany of Pitts.
- gosub 12y ago
  Even Alan Turing, in "On computable numbers, with an application to the Entscheidungsproblem", practically invents turing machines modelling how a mathematician works: He has a pencil, some paper and a number of different states inside his brain.
  - tel 12y ago
    Everyone was directly motivated at the time to solve Hilbert's Entscheidungsproblem [0] which was about mathematical proof not universal machines. Turing, along with a few other mathematicians, recognized that proofs involved notions of algorithms and computation and all, together, generalized these into notions of computation we have today—Turing Machines, Lambda Calculus, Recursive Functions. So it's not terribly surprising that Turing's model was a human one. It was exactly his goal (originally). [0] http://en.wikipedia.org/wiki/Entscheidungsproblem http://en.wikipedia.org/wiki/Entscheidungsproblem
Animats 12y ago
I thought that article was going to be about Leibniz, and his "let us calculate" approach to decision making. "What the Frog's Eye Tells the Frog's Brain" (http://neuromajor.ucr.edu/courses/WhatTheFrogsEyeTellsTheFrogsBrain.pdf http://neuromajor.ucr.edu/courses/WhatTheFrogsEyeTellsTheFro...) is still worth reading. It's the first paper on what is now called "early vision". I'm painfully familiar with that world view. I went through Stanford CS in 1983-1985, when logic-based AI was, in retrospect, having its last gasp. I took "Dr. John's Mystery Hour", Epistemological Problems in Artificial Intelligence, from John McCarthy. The logicians were making progress on solving problems once they'd been hammered into just the right predicate calculus form, but were getting nowhere in translating the real world into predicate calculus. For computer program verification, though, that stuff works. For a time, I was fascinated by Boyer-Moore theory and their theorem prover. They'd redone Russell and Whitehead with machine proofs. Constructive mathematics maps well to what computers can do. I got the Boyer-Moore theorem prover (powerful, could do induction, but slow) hooked up to the Oppen-Nelson theorem prover (limited, only does arithmetic up to multiplication by constants, but fast) and used the combination to build a usable proof-of-correctness system for a dialect of Pascal. It worked fine; I used to invite people to put in a bug in a working program and watch the system find it. But it was clear that approach wasn't going to map to the messiness of the real world. Working on proof of correctness for real programs made it painfully clear how brittle formal logic systems are. Nobody was going to get to common sense that way. The logicians were in denial about this for a long time, which resulted in the "AI winter" from 1985 to 2000 or so. Then came the machine learning guys, and progress resumed. Science progresses one funeral at a time.
- eli_gottlieb 12y ago
  And next come the probabilistic programming guys, I'd bet.
gotrecruit 12y ago
So basically Margaret Weisner was the Yoko of the scientific world?
islon 12y ago
"But three years later, when he heard that Russell would be visiting the University of Chicago, the 15-year-old ran away from home and headed for Illinois. He never saw his family again." Assuming that 80% of humanity lives on less than $10 a day, and are, therefore, poor, I can just imagine the number of geniuses born poor that will not ever be able to show their geniality to the world. Imagine how the world would be a better place with all these people working as scientists, philosophers, mathematicians, etc.
- droque 12y ago
  I've taught in (Mexican) state programs for gifted youth and I can testify that a lot of the kids (many of them poor or almost) end up wasting their potential and having hard times, monetary wise. Meanwhile, significantly less hard working and less bright kids from private schools go on and get comfortable jobs. A local think tank (http://pipe.cide.edu/talento-en-mexico http://pipe.cide.edu/talento-en-mexico) calculated the economical implications of not developing this talent. According to their model, on a 40 year span, developing it would give a 132% increase in the GDP per capita in comparison with staying at current levels.
tripzilch 12y ago
> Nature had chosen the messiness of life over the austerity of logic, a choice Pitts likely could not comprehend. Regarding "Nature had chosen ...", I wonder if this was actually how Pitts saw it (he seemed more clever than that), or whether it is the article's author's misconception that he considered there is in fact something in Nature that "chooses", instead of applying mechanistic rules entirely. It is as if the part of the story about the frogs is meant to show that Nature has a "spirit" after all, that evaded being captured in logic. I can't really fathom why Pitts, after all his history, would come to that conclusion. Just because the retina turned out to possess a certain amount of analog computing power?
axilmar 12y ago
The brain doesn't do logic, it does pattern matching, and selects the appropriate reaction based on the match that offers the biggest chances of survival.

147 points by robgering 12y ago

Having read _Principia_ did Pitts read Kurt Goedel[1]? I would very much like to know what he thought of it! What an incredibly sad story - burning years of work in meloncholy, all thanks to the lies of an angry woman. Wiener, though, shares a great deal of blame - a man should not pass judgement in on his friends without inquiring into the truth of the matter. [1]https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_...

dvt 12y ago
Given that Gödel and Pitts most likely wrote to one another (although their correspondence doesn't survive), it's very probable that they were intimately familiar with the work of one another. There's an entire chapter dedicated to Walter Pitts in Kurt Gödel: Collected Works, Volume V.
leoc 12y ago
Anyone so active in formal logic in mid-C20 (or since) could not possibly have missed Gödel's work.

nanis 12y ago

I thought that was Spinoza.

sowhatquestion 12y ago
I was going to guess Hegel. Either one would work though
- vanderZwan 12y ago
  Wasn't Descartes partially motivated by the horrors of the Thirty Years war?

carapace 12y ago

Such a terrible tragedy, both personal and for the world. I highly recommend the book referenced: "Dark Hero of the Information Age: In Search of Norbert Wiener, the Father of Cybernetics". R.I.P. Walter Pitts (One thing that troubles me slightly: this article mentions a possible cause of the break between Wiener and the others which is presented as speculation in the book, if I remember correctly, but stated here as a bald fact. In any event I wish that Wiener hadn't acted so rashly.)

javert 12y ago

Ayn Rand?

plink 12y ago
logic, not hubris.
xmonkee 12y ago
lol
psychometry 12y ago
I thought this was a joke until I read your HN profile. Then I discovered that the joke is much bigger than this solitary comment.
- dang 12y ago
  Please don't post unduly personal comments on Hacker News.

xmonkee 12y ago

This article is fascinating. I had no idea that the Von Neumann machine was an extrapolation of a mental model. Even more fascinating, that the existince of a symbolic computation machine made the possibility of purely symobolic epistimology impossible. It's like they abstracted a lever higher than they wanted to and then made a cleaner, simpler implementation of it. And now with modern AI we are doubling down on that implementation and trying to build a new kind of intelligence no top of it.

darkmighty 12y ago
It's fascinating that we've built a model of a computer, which was impractical; then we've modeled the brain with very high abstraction and then actually built a computer. Now we're back to modelling the brain because while the abstractions are universal they're not efficient enough. We need to nitty gritty details on efficient ways of learning and computing approximately ("probably approximately correct"), quickly and efficiently. Which is what I believe the article tries to convey as the last epiphany of Pitts.
gosub 12y ago
Even Alan Turing, in "On computable numbers, with an application to the Entscheidungsproblem", practically invents turing machines modelling how a mathematician works: He has a pencil, some paper and a number of different states inside his brain.
- tel 12y ago
  Everyone was directly motivated at the time to solve Hilbert's Entscheidungsproblem [0] which was about mathematical proof not universal machines. Turing, along with a few other mathematicians, recognized that proofs involved notions of algorithms and computation and all, together, generalized these into notions of computation we have today—Turing Machines, Lambda Calculus, Recursive Functions. So it's not terribly surprising that Turing's model was a human one. It was exactly his goal (originally). [0] http://en.wikipedia.org/wiki/Entscheidungsproblem http://en.wikipedia.org/wiki/Entscheidungsproblem

Animats 12y ago

I thought that article was going to be about Leibniz, and his "let us calculate" approach to decision making. "What the Frog's Eye Tells the Frog's Brain" (http://neuromajor.ucr.edu/courses/WhatTheFrogsEyeTellsTheFrogsBrain.pdf http://neuromajor.ucr.edu/courses/WhatTheFrogsEyeTellsTheFro...) is still worth reading. It's the first paper on what is now called "early vision". I'm painfully familiar with that world view. I went through Stanford CS in 1983-1985, when logic-based AI was, in retrospect, having its last gasp. I took "Dr. John's Mystery Hour", Epistemological Problems in Artificial Intelligence, from John McCarthy. The logicians were making progress on solving problems once they'd been hammered into just the right predicate calculus form, but were getting nowhere in translating the real world into predicate calculus. For computer program verification, though, that stuff works. For a time, I was fascinated by Boyer-Moore theory and their theorem prover. They'd redone Russell and Whitehead with machine proofs. Constructive mathematics maps well to what computers can do. I got the Boyer-Moore theorem prover (powerful, could do induction, but slow) hooked up to the Oppen-Nelson theorem prover (limited, only does arithmetic up to multiplication by constants, but fast) and used the combination to build a usable proof-of-correctness system for a dialect of Pascal. It worked fine; I used to invite people to put in a bug in a working program and watch the system find it. But it was clear that approach wasn't going to map to the messiness of the real world. Working on proof of correctness for real programs made it painfully clear how brittle formal logic systems are. Nobody was going to get to common sense that way. The logicians were in denial about this for a long time, which resulted in the "AI winter" from 1985 to 2000 or so. Then came the machine learning guys, and progress resumed. Science progresses one funeral at a time.

eli_gottlieb 12y ago
And next come the probabilistic programming guys, I'd bet.

gotrecruit 12y ago

So basically Margaret Weisner was the Yoko of the scientific world?

islon 12y ago

"But three years later, when he heard that Russell would be visiting the University of Chicago, the 15-year-old ran away from home and headed for Illinois. He never saw his family again." Assuming that 80% of humanity lives on less than $10 a day, and are, therefore, poor, I can just imagine the number of geniuses born poor that will not ever be able to show their geniality to the world. Imagine how the world would be a better place with all these people working as scientists, philosophers, mathematicians, etc.

droque 12y ago
I've taught in (Mexican) state programs for gifted youth and I can testify that a lot of the kids (many of them poor or almost) end up wasting their potential and having hard times, monetary wise. Meanwhile, significantly less hard working and less bright kids from private schools go on and get comfortable jobs. A local think tank (http://pipe.cide.edu/talento-en-mexico http://pipe.cide.edu/talento-en-mexico) calculated the economical implications of not developing this talent. According to their model, on a 40 year span, developing it would give a 132% increase in the GDP per capita in comparison with staying at current levels.

tripzilch 12y ago

> Nature had chosen the messiness of life over the austerity of logic, a choice Pitts likely could not comprehend. Regarding "Nature had chosen ...", I wonder if this was actually how Pitts saw it (he seemed more clever than that), or whether it is the article's author's misconception that he considered there is in fact something in Nature that "chooses", instead of applying mechanistic rules entirely. It is as if the part of the story about the frogs is meant to show that Nature has a "spirit" after all, that evaded being captured in logic. I can't really fathom why Pitts, after all his history, would come to that conclusion. Just because the retina turned out to possess a certain amount of analog computing power?

axilmar 12y ago

The brain doesn't do logic, it does pattern matching, and selects the appropriate reaction based on the match that offers the biggest chances of survival.