Later, Wheeler was no less imaginative in his thinking about information theory. He believed that information is not a secondary concept, but fundamental to the Universe. He coined the shorthand “it from bit” for the concept that every entity — every particle, every field and even space-time — derives its meaning from ideas in information theory.
In dreamless sleep and general anaesthesia, these echoes are very simple, like the waves generated by throwing a stone into still water. But during conscious states, a typical echo ranges widely over the cortical surface, disappearing and reappearing in complex patterns. Excitingly, we can now quantify the complexity of these echoes by working out how compressible they are, similar to how simple algorithms compress digital photos into JPEG files. The ability to do this represents a first step towards a ‘consciousness-meter’ that is both practically useful and theoretically motivated.