There has been a spate of outbursts from physicists who should know better, including Stephen Hawking, saying ‘philosophy is dead – all we need now is physics’ or words to that effect. I challenge any of them to read this book and still say that philosophy is pointless.

It’s worth pointing out immediately that this isn’t really a popular science book. I’d say the first handful of chapters are for everyone, but after that, the bulk of the book would probably be best for undergraduate philosophy students or AI students, reading more like a textbook than anything else, particularly in its dogged detail – but if you are interested in philosophy and/or artificial intelligence, don’t let that put you off.

What Nick Bostrom does is to look at the implications of developing artificial intelligence that goes beyond human abilities in the general sense. (Of course, we already have a sort of AI that goes beyond our abilities in the narrow sense of, say, arithmetic, or playing chess.) In the first couple of chapters he examines how this might be possible – and points out that the timescale is very vague. (Ever since electronic computers have been invented, pundits have been putting the development of effective AI around 20 years in the future, and it’s still the case.) Even so, it seems entirely feasible that we will have a more than human AI – a superintelligent AI – by the end of the century. But the ‘how’ aspect is only a minor part of this book.

The real subject here is how we would deal with such a ‘cleverer than us’ AI. What would we ask it to do? How would we motivate it? How would we control it? And, bearing in mind it is more intelligent than us, how would we prevent it taking over the world or subverting the tasks we give it to its own ends? It is truly fascinating concept, explored in great depth here. This is genuine, practical philosophy. The development of super-AIs may well happen – and if we don’t think through the implications and how we would deal with it, we could well be stuffed as a species.

I think it’s a shame that Bostrom doesn’t make more use of science fiction to give examples of how people have already thought about these issues – he gives only half a page to Asimov and the three laws of robotics (and how Asimov then spends most of his time showing how they’d go wrong), but that’s about it. Yet there has been a lot of thought and dare I say it, a lot more readability than you typically get in a textbook, put into the issues in science fiction than is being allowed for, and it would have been worthy of a chapter in its own right.

I also think a couple of the fundamentals aren’t covered well enough, but pretty much assumed. One is that it would be impossible to contain and restrict such an AI. Although some effort is put into this, I’m not sure there is enough thought put into the basics of ways you can pull the plug manually – if necessary by shutting down the power station that provides the AI with electricity.

The other dubious assertion was originally made by I. J. Good, who worked with Alan Turing, and seems to be taken as true without analysis. This is the suggestion that an ultra-intelligent machine would inevitably be able to design a better AI than humans, so once we build one it will rapidly improve on itself, producing an ‘intelligence explosion’. I think the trouble with this argument is that my suspicion is that if you got hold of the million most intelligent people on earth, the chances are that none of them could design an ultra-powerful computer at the component level. Just because something is superintelligent doesn’t mean it can do this specific task well – this is an assumption.

However this doesn’t set aside what a magnificent conception the book is. I don’t think it will appeal to many general readers, but I do think it ought to be required reading on all philosophy undergraduate courses, by anyone attempting to build AIs… and by physicists who think there is no point to philosophy.