Philosophers/physicists have long drawn parallels between information theory and quantum theory. The contention that the physical world is built, ultimately, of information — that the distinction between the world and information about the world is murky — has troubled me, until I read this description of Viennese physicist Anton Zeilinger’s explanation of quantum mechanics.
It sounds innocuous. But the consequences of Zeilinger’s principle promise to be breathtaking. In the first place, it contains the fact that the world is quantised–the very starting point of quantum mechanics. Because we can only interrogate nature the way a lawyer interrogates a witness, by means of simple yes-or-no questions, we should not be surprised that the answers come in discrete chunks. Because there is a finest grain to information there has to be a finest grain to our experience of nature. This is why electrons are restricted to fixed energy levels in atoms, why light comes in pieces we call photons, and perhaps, ultimately, why the Universe seems to be made out of discrete particles. To the question, “Why does the world appear to be quantised?” Zeilinger replies, “Because information about the world is quantised.” ‘ (New Scientist)
