INFORMATION PHYSICS: AS A PROJECTION OF THE SUBSTRATE

For a century we have been told two contradictory things about information. The first is that the universe is secretly made of it - that beneath the atoms there are only bits, that reality is at bottom a kind of code. The second is that "information physics" is fashionable hand-waving, a buzzword dressed up as a discipline. Both verdicts miss what is actually the case, and the truth is stranger and simpler than either. Information is not a substance the world is built from. It is the name we give to one undeniable fact: that the world is differentiated - shot through with differences rather than blank, silent sameness. Every famous way of measuring information - the bits that travel down a wire, the length of the shortest description, the entropy of a warm room, the heat released when a memory is erased, the meaning a signal carries to whoever is listening - turns out to be a faithful shadow of that single fact, cast from a different angle. >Information physics; entropy; information theory; complexity; thermodynamics; cosmology; reality