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.

Underneath the shifting appearances of the world as perceived by our unreliable senses, is there, or is there not, a bedrock of objective reality?

An electron is real; a probability is not.

Information gently but relentlessly drizzles down on us in an invisible, impalpable electric rain.

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.

Science has taught us that what we see and touch is not what is really there.

To put it one way, a collection of Shakespeare's plays is richer than a phone book that uses the same number of letters; to put it another, the essence of information lies in the relationships among bits, not their sheer number.