In order to understand information, we must define it; bit in order to define it, we must first understand it. Where to start?

Claude Shannon, the founder of information theory, invented a way to measure 'the amount of information' in a message without defining the word 'information' itself, nor even addressing the question of the meaning of the message.

Numbers instill a feeling for the lie of the land, and furnish grist for the mathematical mill that is the physicist's principal tool.

This is not what I thought physics was about when I started out: I learned that the idea is to explain nature in terms of clearly understood mathematical laws; but perhaps comparisons are the best we can hope for.

The smell of subjectivity clings to the mechanical definition of complexity as stubbornly as it sticks to the definition of information.

Time has been called God's way of making sure that everything doesn't happen at once. In the same spirit, noise is Nature's way of making sure that we don't find out everything that happens. Noise, in short, is the protector of information.

As every bookie knows instinctively, a number such as reliability - a qualitative rather than a quantitative measure - is needed to make the valuation of information practically useful.