Tag Archives: Hassabis

AI turns the corner?

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Is the latest version of AlphaZero showing signs of human style intuition and creativity?

The current AlphaZero is a more generalised version of the program, produced by Demis Hassabis and his team, that beat top human players of Go for the first time. The new version, presented briefly in Science magazine, is able to learn a range of different games; besides Go it learned chess and shogi, and apparently reached world-class play in all of them.

The Science article, by David Silver et al, modestly says this achievement is an important step towards a fully-general game-playing program, but press reports went further, claiming that in chess particularly AlphaZero showed more human traits than any previous system. It reinvented human strategies and sacrificed pieces for advantage fairly readily, the way human players do; chess commentators said that its play seemed to have new qualities of insight and intuition.

This is somewhat unexpected, because so far as I can tell the latest version is in fact not a radical change from its predecessors; in essence it uses the same clever combination of appropriate algorithms with a deep neural network, simply applying them more generally. It does appear that the approach has proved more widely powerful than we might have expected, but it is no more human in nature than the earlier versions and does not embody any new features copied from real brains. It learns its games from scratch, with only the rules to go on, playing out games against itself repeatedly in order to find what works. This is not much like the way humans learn chess; I think you would probably die of boredom after a few hundred games, and even if you survived, without some instruction and guidance you would probably never learn to be a good player, let alone a superlative one. However, running through possible games in one’s mind may be quite like what a good human player does when trying to devise new strategies.

The key point for me is that although the new program is far more general in application, it still only operates in the well-defined and simple worlds provided by rule-governed games. To be anything like human, it needs to display the ability to deal with the heterogenous and undefinable world of real life. That is still far distant (Hassabis himself has displayed an awareness of the scale of the problem, warning against releasing self-driving cars on to real roads prematurely), though I don’t altogether rule out the possibility that we are now moving perceptibly in the right direction.

Someone who might deny that is Gary Marcus, who in a recent Nautilus piece set out his view that deep learning is simply not enough. It needs, he says, to be supplemented by other tools, and in particular it needs symbol manipulation.

To me this is confusing, because I naturally interpret ‘symbol manipulation’ as being pretty much a synonym for Turing style computation. That’s the bedrock of any conventional computer, so it seems odd to say we need to add it. I suppose Marcus is using the word ‘symbol’ in a different sense. The ones and zeroes shuffled around by a Turing machine are meaningless to the machine. We assign a meaning to the input and so devise the manipulations that the output can be given an interpretation which makes it useful or interesting to us, but the machine itself knows nothing of that. Marcus perhaps means that we need a new generation of machines that can handle symbols according to their meanings.

If that’s it, then few would disagree that that is one of the ultimate aims. Those who espouse deep learning techniques merely think that those methods may in due course lead to a machine that handles meanings in the true sense; at some stage the system will come up with the unknown general strategy that enables it to get meaningful and use symbols the way a human would. Marcus presumably thinks that is hopeless optimism, on the scale of those people who think any system that is sufficiently complex will naturally attain self-awareness.

Since we don’t have much of an idea how the miracle of meaning might happen it is indeed optimistic to think we’re on the road towards it. How can a machine bootstrap itself into true ‘symbol manipulation’ without some kind of help? But we know that the human brain must have done just that at some stage in evolution – and indeed each of our brains seem to have done it again during our development. It has got to be possible. Optimistic yes, hopeless – maybe not.

Go AI

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Go boardThe recent victory scored by the AlphaGo computer system over a professional Go player might be more important than it seems.

At first sight it seems like another milestone on a pretty well-mapped road; significant but not unexpected. We’ve been watching games gradually yield to computers for many years; chess notoriously, was one they once said was permanently out of the reach of the machines. All right, Go is a little bit special. It’s an extremely elegant game; from some of the simplest equipment and rules imaginable it produces a strategic challenge of mind-bending complexity, and one whose combinatorial vastness seems to laugh scornfully at Moore’s Law – maybe you should come back when you’ve got quantum computing, dude! But we always knew that that kind of confidence rested on shaky foundations; maybe Go is in some sense the final challenge, but sensible people were always betting on its being cracked one day.

The thing is, Go has not been beaten in quite the same way as chess. At one time it seemed to be an interesting question as to whether chess would be beaten by intelligence – a really good algorithm that sort of embodied some real understanding of chess – or by brute force; computers that were so fast and so powerful they could analyse chess positions exhaustively. That was a bit of an oversimplification, but I think it’s fair to say that in the end brute force was the major factor. Computers can play chess well, but they do it by exploiting their own strengths, not by doing it through human-style understanding. In a way that is disappointing because it means the successful systems don’t really tell us anything new.

Go, by contrast, has apparently been cracked by deep learning, the technique that seems to be entering a kind of high summer of success. Oversimplifying again, we could say that the history of AI has seen a contest between two tribes; those who simply want to write programs that do what’s needed, and those that want the computer to work it out for itself, maybe using networks and reinforcement methods that broadly resemble the things the human brain seems to do. Neither side, frankly, has altogether delivered on its promises and what we might loosely call the machine learning people have faced accusations that even when their systems work, we don’t know how and so can’t consider them reliable.

What seems to have happened recently is that we have got better at deploying several different approaches effectively in concert. In the past people have sometimes tried to play golf with only one club, essentially using a single kind of algorithm which was good at one kind of task. The new Go system, by contrast, uses five different components carefully chosen for the task they were to perform; and instead of having good habits derived from the practice and insights of human Go masters built in, it learns for itself, playing through thousands of games.

This approach takes things up to a new level of sophistication and clearly it is yielding remarkable success; but it’s also doing it in a way which I think is vastly more interesting and promising than anything done by Deep Thought or Watson. Let’s not exaggerate here, but this kind of machine learning looks just a bit more like actual thought. Claims are being made that it could one day yield consciousness; usually, if we’re honest, claims like that on behalf of some new system or approach can be dismissed because on examination the approach is just palpably not the kind of thing that could ever deliver human-style cognition; I don’t say deep learning is the answer, but for once, I don’t think it can be dismissed.

Demis Hassabis, who led the successful Google DeepMind project, is happy to take an optimistic view; in fact he suggests that the best way to solve the deep problems of physics and life may be to build a deep-thinking machine clever enough to solve them for us (where have I heard that idea before?). The snag with that is that old objection; the computer may be able to solve the problems, but we won’t know how and may not be able to validate its findings. In the modern world science is ultimately validated in the agora; rival ideas argue it out and the ones with the best evidence wins the day. There are already some emergent problems, with proofs achieved by an exhaustive consideration of cases by computation that no human brain can ever properly validate.

More nightmarish still the computer might go on to understand things we’re not capable of understanding. Or seem to: how could we be sure?