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Oct
28th
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Douglas Hofstadter: The Man Who Would Teach Machines to Think

"All the limitative theorems of metamathematics and the theory of computation suggest that once the ability to represent your own structure has reached a certain critical point, that is the kiss of death: it guarantees that you can never represent yourself totally. Gödel’s Incompleteness Theorem, Church’s Undecidability Theorem, Turing’s Halting Theorem, Tarski’s Truth Theorem — all have the flavour of some ancient fairy tale which warns you that “To seek self-knowledge is to embark on a journey which … will always be incomplete, cannot be charted on any map, will never halt, cannot be described.”

Douglas Hofstadter, 1979, cited in Vinod K. Wadhawan, Complexity Explained: 17. Epilogue, Nirmukta, 04 April 2010.

image M. C. Escher, Print Gallery. Hofstadter calls this Escher work a “pictorial parable for Godel’s Incompleteness Theorem.” Why? Look to the center of the painting, is there any way logical way to complete it? — source (Click picture to enlarge)

"On [Douglas] Hofstadter's office wall is a somewhat tattered reproduction of one of his favorite mind-twisting M. C. Escher prints, The Print Gallery.” In it, a boy stands looking at a print depicting a town where a woman looks down from her window at the roof of a gallery in which - yes - the boy stands looking at the print. We appreciate the paradox without being thrown by it, because we are outside looking in. Something like that creates our own unfathomable feelings of self. The self, subject and object, perceiver and perceived, is everywhere in the paradox.

It is a ”circling back,” the Tortoise tells Achilles, ”of a complex representation of the system together with its representations of all the rest of the world.”

”It is just so hard, emotionally,” Achilles tells the Tortoise, ”to acknowledge that a ‘soul’ emerges from so physical a system.” (…)

But philosophers like  [Daniel] Dennett believe, with Hofstadter, that scientific answers can be found without cheating by reducing the question to a manageable scale. (…) [T]he danger of looking only at the lowest biological level is in losing sight of the essential humanity that, in Hofstadter’s view, exists in the pattern and in the paradox. ”There seems to be no alternative to accepting some sort of incomprehensible quality to existence,” as Hofstadter puts it. ”Take your pick.” 

James Gleick, on Douglas R. Hofstadter in Exploring the Labyrinth of the Mind, The New York Times, August 21, 1983.

"In 1931, the Austrian-born logician Kurt Gödel had famously shown how a mathematical system could make statements not just about numbers but about the system itself. Consciousness, Hofstadter wanted to say, emerged via just the same kind of “level-crossing feedback loop.” (…)

“Cognition is recognition,” he likes to say. He describes “seeing as” as the essential cognitive act: you see some lines as “an A,” you see a hunk of wood as “a table,” you see a meeting as “an emperor-has-no-clothes situation” and a friend’s pouting as “sour grapes” and a young man’s style as “hipsterish” and on and on ceaselessly throughout your day. That’s what it means to understand. But how does understanding work? For three decades, Hofstadter and his students have been trying to find out, trying to build “computer models of the fundamental mechanisms of thought.”

“At every moment,” Hofstadter writes in Surfaces and Essences, his latest book (written with Emmanuel Sander), “we are simultaneously faced with an indefinite number of overlapping and intermingling situations.” It is our job, as organisms that want to live, to make sense of that chaos. We do it by having the right concepts come to mind. This happens automatically, all the time. Analogy is Hofstadter’s go-to word. The thesis of his new book, which features a mélange of A’s on its cover, is that analogy is “the fuel and fire of thinking,” the bread and butter of our daily mental lives.

“Look at your conversations,” he says. “You’ll see over and over again, to your surprise, that this is the process of analogy-making.” Someone says something, which reminds you of something else; you say something, which reminds the other person of something else—that’s a conversation. It couldn’t be more straightforward. But at each step, Hofstadter argues, there’s an analogy, a mental leap so stunningly complex that it’s a computational miracle: somehow your brain is able to strip any remark of the irrelevant surface details and extract its gist, its “skeletal essence,” and retrieve, from your own repertoire of ideas and experiences, the story or remark that best relates.

“Beware,” he writes, “of innocent phrases like ‘Oh, yeah, that’s exactly what happened to me!’ … behind whose nonchalance is hidden the entire mystery of the human mind.” (…)

[Hofstadter] spends most of his time in his study, two rooms on the top floor of his house, carpeted, a bit stuffy, and messier than he would like. His study is the center of his world. He reads there, listens to music there, studies there, draws there, writes his books there, writes his e‑mails there. (Hofstadter spends four hours a day writing e‑mail. “To me,” he has said, “an e‑mail is identical to a letter, every bit as formal, as refined, as carefully written … I rewrite, rewrite, rewrite, rewrite all of my e‑mails, always.”) He lives his mental life there, and it shows. Wall-to-wall there are books and drawings and notebooks and files, thoughts fossilized and splayed all over the room. It’s like a museum for his binges, a scene out of a brainy episode of Hoarders.

“Anything that I think about becomes part of my professional life,” he says. Daniel Dennett, who co-edited The Mind’s I with him, has explained that “what Douglas Hofstadter is, quite simply, is a phenomenologist, a practicing phenomenologist, and he does it better than anybody else. Ever.” He studies the phenomena—the feelings, the inside actions—of his own mind. “And the reason he’s good at it,” Dennett told me, “the reason he’s better than anybody else, is that he is very actively trying to have a theory of what’s going on backstage, of how thinking actually happens in the brain.” (…)

He makes photocopies of his notebook pages, cuts them up with scissors, and stores the errors in filing cabinets and labeled boxes around his study.

For Hofstadter, they’re clues. “Nobody is a very reliable guide concerning activities in their mind that are, by definition, subconscious,” he once wrote. “This is what makes vast collections of errors so important. In an isolated error, the mechanisms involved yield only slight traces of themselves; however, in a large collection, vast numbers of such slight traces exist, collectively adding up to strong evidence for (and against) particular mechanisms.” Correct speech isn’t very interesting; it’s like a well-executed magic trick—effective because it obscures how it works. What Hofstadter is looking for is “a tip of the rabbit’s ear … a hint of a trap door.

As the wind tunnel was to the Wright brothers, so the computer is to FARG. The quick unconscious chaos of a mind can be slowed down on the computer, or rewound, paused, even edited. In Hofstadter’s view, this is the great opportunity of artificial intelligence. Parts of a program can be selectively isolated to see how it functions without them; parameters can be changed to see how performance improves or degrades. When the computer surprises you—whether by being especially creative or especially dim-witted—you can see exactly why. “I have always felt that the only hope of humans ever coming to fully understand the complexity of their minds,” Hofstadter has written, “is by modeling mental processes on computers and learning from the models’ inevitable failures.” (…)

But very few people, even admirers of GEB, know about the book or the programs it describes. And maybe that’s because FARG’s programs are almost ostentatiously impractical. Because they operate in tiny, seemingly childish “microdomains.” Because there is no task they perform better than a human.

The modern era of mainstream AI—an era of steady progress and commercial success that began, roughly, in the early 1990s and continues to this day—is the long unlikely springtime after a period, known as the AI Winter, that nearly killed off the field.

It came down to a basic dilemma. On the one hand, the software we know how to write is very orderly; most computer programs are organized like a well-run army, with layers of commanders, each layer passing instructions down to the next, and routines that call subroutines that call subroutines. On the other hand, the software we want to write would be adaptable—and for that, a hierarchy of rules seems like just the wrong idea. Hofstadter once summarized the situation by writing, “The entire effort of artificial intelligence is essentially a fight against computers’ rigidity.”

Machine learning

The “expert systems” that had once been the field’s meal ticket were foundering because of their brittleness. Their approach was fundamentally broken. Take machine translation from one language to another, long a holy grail of AI. The standard attack involved corralling linguists and translators into a room and trying to convert their expertise into rules for a program to follow. The standard attack failed for reasons you might expect: no set of rules can ever wrangle a human language; language is too big and too protean; for every rule obeyed, there’s a rule broken.

If machine translation was to survive as a commercial enterprise—if AI was to survive—it would have to find another way. Or better yet, a shortcut.

The technique is called “machine learning.” The goal is to make a device that takes an English sentence as input and spits out a French sentence. One such device, of course, is the human brain—but the whole point is to avoid grappling with the brain’s complexity. So what you do instead is start with a machine so simple, it almost doesn’t work: a machine, say, that randomly spits out French words for the English words it’s given.

Imagine a box with thousands of knobs on it. Some of these knobs control general settings: given one English word, how many French words, on average, should come out? And some control specific settings: given jump, what is the probability that shot comes next? The question is, just by tuning these knobs, can you get your machine to convert sensible English into sensible French?

It turns out that you can. What you do is feed the machine English sentences whose French translations you already know. (Candide, for example, used 2.2 million pairs of sentences, mostly from the bilingual proceedings of Canadian parliamentary debates.) You proceed one pair at a time. After you’ve entered a pair, take the English half and feed it into your machine to see what comes out in French. If that sentence is different from what you were expecting—different from the known correct translation—your machine isn’t quite right. So jiggle the knobs and try again. After enough feeding and trying and jiggling, feeding and trying and jiggling again, you’ll get a feel for the knobs, and you’ll be able to produce the correct French equivalent of your English sentence.

By repeating this process with millions of pairs of sentences, you will gradually calibrate your machine, to the point where you’ll be able to enter a sentence whose translation you don’t know and get a reasonable result. And the beauty is that you never needed to program the machine explicitly; you never needed to know why the knobs should be twisted this way or that. (…)

Google has projects that gesture toward deeper understanding: extensions of machine learning inspired by brain biology; a “knowledge graph” that tries to map words, like Obama, to people or places or things. But the need to serve 1 billion customers has a way of forcing the company to trade understanding for expediency. You don’t have to push Google Translate very far to see the compromises its developers have made for coverage, and speed, and ease of engineering. Although Google Translate captures, in its way, the products of human intelligence, it isn’t intelligent itself. It’s like an enormous Rosetta Stone, the calcified hieroglyphics of minds once at work. (…)

Ever since he was about 15, Hofstadter has read The Catcher in the Rye once every 10 years. In the fall of 2011, he taught an undergraduate seminar called “Why Is J. D. Salinger’s The Catcher in the Rye a Great Novel?” He feels a deep kinship with Holden Caulfield. When I mentioned that a lot of the kids in my high-school class didn’t like Holden—they thought he was a whiner—Hofstadter explained that “they may not recognize his vulnerability.” You imagine him standing like Holden stood at the beginning of the novel, alone on the top of a hill, watching his classmates romp around at the football game below. “I have too many ideas already,” Hofstadter tells me. “I don’t need the stimulation of the outside world.” (…)

“Ars longa, vita brevis,” Hofstadter likes to say. “I just figure that life is short. I work, I don’t try to publicize. I don’t try to fight.”

There’s an analogy he made for me once. Einstein, he said, had come up with the light-quantum hypothesis in 1905. But nobody accepted it until 1923. “Not a soul,” Hofstadter says. “Einstein was completely alone in his belief in the existence of light as particles—for 18 years.

“That must have been very lonely.” “

— James Somers, to read the full article click The Man Who Would Teach Machines to Think, The Atlantic, Oct 23 2013

Douglas Hofstadter, is an American professor of cognitive science whose research focuses on the sense of “I”, consciousness, analogy-making, artistic creation, literary translation, and discovery in mathematics and physics. He is best known for his book Gödel, Escher, Bach: an Eternal Golden Braid, first published in 1979. It won both the Pulitzer Prize for general non-fiction.

See also:

The Mathematical Art of M.C. Escher, Lapidarium notes