Intelligence in the Universe

Whether or not we as humans are the only examples of intelligence in the universe is one of the great unanswered questions of science.

Just how intelligence should be defined has never been quite clear. But in recent times it has usually been assumed that it has something to do with an ability to perform sophisticated computations.

And with traditional intuition it has always seemed perfectly reasonable that it should take a system as complicated as a human to exhibit such capabilities—and that the whole elaborate history of life on Earth should have been needed to generate such a system.

With the development of computer technology it became clear that many features of intelligence could be achieved in systems that are not biological. Yet our experience has still been that to build a computer requires sophisticated engineering that in a sense exists only because of human biological and cultural development.

But one of the central discoveries of this book is that in fact nothing so elaborate is needed to get sophisticated computation. And indeed the Principle of Computational Equivalence implies that a vast range of systems—even ones with very simple underlying rules—should be equivalent in the sophistication of the computations they perform.

So in as much as intelligence is associated with the ability to do sophisticated computations it should in no way require billions of years of biological evolution to produce—and indeed we should see it all over the place, in all sorts of systems, whether biological or otherwise.

And certainly some everyday turns of phrase might suggest that we do. For when we say that the weather has a mind of its own we are in effect attributing something like intelligence to the motion of a fluid. Yet surely, one might argue, there must be something fundamentally more to true intelligence of the kind that we as humans have.

So what then might this be?

Certainly one can identify all sorts of specific features of human intelligence: the ability to understand language, to do mathematics, solve puzzles, and so on. But the question is whether there are more