Abstract
Quantum theory and the classical theory of computation were perfected in the 1930s, and fifty years later they were unified to form the quantum theory of computation. Here I want to tell you about a speculation — I can’t call it more than a “speculation” even though I know it’s true — about the kind of theory that might, in another fifty years’ time, supersede or transcend the quantum theory of computation. There are branches of science — in fact most of them are branches of physics — that we expect, by their nature, to have philosophical implications. An obvious example is cosmology. There are other sciences, such as, say, aerodynamics, in which, no matter how startling or important our discoveries may become, we do not expect fundamental philosophical implications. So, various sciences fall at different places on a scale (Fig. 1) ranging from the most fundamental on the left to the least fundamental, the most derivative, on the right.