sábado, julho 22, 2017

Beyond the Usual Alpha-Beta Search: "Deep Thinking - Where Machine Intelligence Ends and Human Creativity Begins” by Garry Kasparov, Mig Greengard



“In 2016, nineteen years after my loss to Deep Blue, the Google-backed AI project DeepMind and its Go-playing offshoot AlphaGo defeated the world’s top Go player, Lee Sedol. More importantly, as also as predicted, the methods used to create AlphaGo were more interesting as an IA Project than anything that had produced the top chess machines. It uses machine learning and neural networks to teach itself how to play better, as well as other sophisticated techniques beyond the usual alpha-beta search. Deep Blue was the end; AlphaGo is a beginning.”

In “Deep Thinking - Where Machine Intelligence Ends and Human Creativity Begins” by Garry Kasparov, Mig Greengard 

My personal experience with Go dates back at least a decade. I remember getting slaughtered every time by the free GNUgo software, just as I had been by every human opponent for the last 20 years. Never got the hang of it, though I was school chess captain back in the day. Totally different mindset. I first came across it in a little-remembered crime series called 'The Man in Room 17', with Richard Vernon and Denholm Ellit eponymously solving crimes without leaving their office, where they were always playing go. I also remember a funny little story while I was attending the British Council. Back in the 80s, a Korean guy gave me a game. After every move I played, he stifled a laugh and started a rapid fire of, "No! Cos you purrin ['put in', I presume] there, then I purrin here, after you purrin there an' I purrin here, you lose these piece" None of which made anything clearer. At chess, the first (okay, tenth) time I got mated on the back row by a rook, I learned not to leave the king behind a wall of pawns. Never got my head round the simplest 'joseki' (corner opening) at Go. Beautifully elegant game though.

When reading about the game in Kasparov’s book, I just got sidetracked. Back in the day, along with Chess, I tried to develop a Go AI engine. Sad to say, I could never build it to my full satisfaction; I was able to beat it 9 out of 10 times.  Not so with chess. My AI Chess developed in C, if I may say so, was quite good. Does AlphaGo's success tell us something about the mindfulness of its technology, or does it instead tell us something about the mindlessness of games like chess and Go? Back in the day I studied AphaGo's performance, and impressed though I was by its playing strength, I did notice that it seemed to not understand two basic concepts of Go called "sente" (seizing the initiative) and "aji" (leaving a rock in the road for the opponent to trip over later), as was evidenced by opportunities it missed. What is quite remarkable is that AlphaGo doesn't understand a single thing about Go, except how to count the final score! AlphaGo circumvents the problem of understanding the toy world of Go by using two mathematical tricks: (1) learning knee-jerk reactions and (2) statistically sensible guesswork. A knee-jerk reaction is an automatic reaction to an event that seems to match a pattern; we rely upon such reactions to avoid dangers such as the edge of a cliff or a fire. Such reactions are essential for survival, but they are also unreliable because what we think we see is not always what is there. A pretty face does not necessarily imply a pretty mind. Anyone who has used Google's search engine will know that whereas it is superb at finding information, it is also somewhat clueless as it pulls up a wastepaper basketful of irrelevant snow as well as the one or two nuggets you were looking for. Because Google doesn't speak English. It knows nothing about the world we live in so relies instead solely upon statistical pattern matching to find its answers, much the same as IBM's Jeopardy champ "Watson" does. Jeopardy and document search are tasks well-suited to mindless association-seeking. AlphaGo is of the same breed as Google search and Watson; there are nuances of difference in their pattern-matching algorithms, but the underlying principle is the same: they all search for matching patterns, without troubling to understand what the patterns mean in terms of an ontology of cause and effect. In AlphaGo's case, the patterns it looks for are ones it has inferred by using an artificial intelligence technology called an "(artificial) neural network" that has had some success in learning to recognise a specific object in photographs - most famously, whether there is a cat in a YouTube video.

A Go game in progress is nothing more complicated than a very simple digital photograph, made of just 19x19 pixels, each of which can have just one of three colours: black, white, or empty. So people thought that what works for seeing cats in videos might also work for seeing good moves in Go.

And it does.

In convolutions of artificial neurons, information flows both ways through a stratified network. They are capable of learning patterns more complex than simple one-way networks - although perhaps it would be better to say that they can learn probable patterns, since the mathematics they use creates a probability spectrum of possible identifications. And that is just what's needed to play Go against people, for not even a Go grand-master can say unequivocally what is the best move in the middle of a game. AlphaGo's neural network was trained by showing it what good players did in over 30 million positions taken from a database of expert-level games. It produces a spectrum of knee-jerk reaction good move possibilities, but it doesn't stop there. It goes on to imagine what might happen in the future. AlphaGo's future-guessing methods are different from those used by Deep Blue to defeat chess champ Gary Kasparov, but both their methods are essentially brute-force techniques, relying on sampling millions of possible sequences rather than examining a few pertinent lines by goal-directed knowledge-based search.

AlphaGo can do one thing that Deep Blue could not: it can learn. Right now, it is learning to improve its stockpile of patterns by playing itself every day and teaching itself which moves worked out well during those experiments. However, the rate of improvement of a convolutional neural network reduces over time, so there is every reason to doubt that AlphaGo will become strong enough to beat Lee Sedol.

Nevertheless, both Deep Blue and AlphaGo have reached a game-playing ability higher than 99% of those of us who have also tried to play chess or Go, so we humans should perhaps hang our heads in shame at being so incompetent at reasoning that an unreasoning machine can better us at games we thought to be intellectual challenges requiring sophisticated strategy and tactics! However, although computers can now beat us at board games as well as see a cat in a video, we need not fear that they are about to take over the world and turn us into their domesticated animals. The 0.1% have already won that game.

NB: I closely followed the match between Deep Blue and Kasparov at the time. The 6th (last) game was especially unfathomable. I remember thinking how could Kasparov play into a well-known opening trap in the Caro-Kann. WTF? When a world champion plays like a beginner, there is not much to be said, and much to be sad about. It wasn’t that Deep Blue “outmaneuvered” Kasparov, it was that Kasparov defeated himself. My disenchantment with chess started with this specific game. This match was a travesty and I never recovered from it.


4 comentários:

Book Stooge disse...

My only contact with "Go" is through the manga "Hikaru no go" that I read back in '08. I tried to play a couple of games on some freeware and lost so badly that I never tried again. It is such a different mindset, as you noted, that I just can't grasp the necessary strategy.

"so we humans should perhaps hang our heads in shame at being so incompetent at reasoning that an unreasoning machine can better us at games we thought to be intellectual challenges requiring sophisticated strategy and tactics"

Well, I'd like to ask that ai system to ride a bike. Or color a picture within the lines. It can't. It wasn't designed to. Humans haven't been designed to all excel at the same thing. But we can do about eleventy billion DIFFERENT things. Those machines are precision instruments meant to do one thing extremely well. Now, I'll be worried when cyborgs can start having physical presence in titanium shells. Or when cars, planes, etc start thinking for themselves.

However, I always think they'll fail eventually. Because humans are flawed, their work is flawed and their assumptions and their biases, etc are all flawed. Whatever they do will be flawed as well. Now, that doesn't mean something won't destroy us all WITH its flaws, lol...

Manuel Antão disse...

Most of our beloved jobs and so-called careers were redundant in the first place. AI not only shines a light on our own futility, but will also allow us to bask in what we truly relish as a species: self-absorbed naval gazing. Which is ok, because technology will soon be able to provide the food, clothing, and shelter for which we worry and work so hard for, but at minimal or almost free cost. The paradigm shift swings upon us--bring on Universal Basic Income! Certainly an exciting time for humanity.

What's the point of the rat race if robots are doing all the work anyway? Universal income, humane population management, aggressive push to colonize the rest of the solar system and beyond...and of course the scrapping of the whole "life=work=money" notion that the wealthy few use to enslave the rest of us billions.

Luís Filipe Franco disse...

I must say that Im begining to agree with a vision of complementary humans to excendentary robots. Everywhere you go you see machinery taking human jobs, not because they are cheaper but because they can't find the people to work doing that jobs...
Check agricultural crops nowadays. Even grape crops are machines I heard in reguengos de monsaraz where i was last weekend.
The emigration rate was so high in the last 5 years that the crops had to be done by machines!

Maybe we just have to have only naval-gazing jobs afterall...!!!

Manuel Antão disse...

Luis, that's a very interesting piece there; let's hope that it does not continue to be the case. It is clear that some areas will suffer though, and the creation of different types of work will be essential. One day it'll all be in the history books...