Three kinds of randomness...
Garfinkel mentioned another interesting thing. He is, apparently, working on a book about randomness. He has found, he claims, that there are three kinds of randomness:
1) Quantum randomness - thermal noise, atomic degeneration represents a certain kind of randomness often referred to as true randomness. This randomness is fascinating in that we think that it is ontological, a physical quality.
2) Pseudo-randomness - where we can deduce what seems random as long as we have the seed. This is the kind of randomness found in random number generators.
3) Computational randomness - the easiest way to describe this is to say that a string is random if and only iff the shortest program that generates the string is as long as or longer than the string (no, that is sloppy, I will have to correct this later).
The really interesting thing is of course that we lack ways of figuring out what kind of randomness we are actually facing. What if quantum randomness is in fact pseudo-randomness? That would confirm Einsteins old comment that God does not play with dice...
Things about computational randomness and algorithmic complexity can be found here: