[W]hat we call yesterday is self-contained and has its experience of being yesterday, and today has memories of yesterday; and therefor I say that it… - Julian Barbour

[T]ime is really an illusion... and motion too... [T]hey are not really there in the external world. They are put into the world by us, in the way we interpret it, and by our brains...

The concepts of message and probability enable one, for a definite source of <math>N</math> messages, to define Shannon’s information. If <math>p_i,\quad i = 1, 2, ..., N</math>, is the relative probability of message <math>i</math> and <math>\log p_i</math> is its base-2 logarithm, then the information <math>I</math> of the given source is(1) <math>\quad I = - \sum_{k=1}^N p_i \log p_i</math>.The minus sign makes <math>I</math> positive because all probabilities, which are necessarily greater than or equal zero, are less than unity (their sum being<math>\textstyle \sum_{i}^N p_i = 1</math>, so that their logarithms are all negative.

(quote at 14:08 of 1:54:14)