Chance vs Randomness
Is the Commonplace Thesis
Something is random iff it happens by chance.
correct?
It is hard to define chance, but randomness has a good definition in terms of Kolmogorov/Martin-Lof randomness, thus we may refine the Commonplace Thesis into:
- (A) A sequence of outcomes happens by chance iff that sequence is random.
- (B) An outcome happens by chance iff there is a random sequence of outcomes including it.
- (R) An outcome happens by chance iff, were the trial which generated that outcome repeated often enough under the same conditions, a random sequence including the outcome will obtain.
If it is not. Then
- Random occurances still may be explained.
- No statistical inferences on the basis of randomly sampling a large population will be valid.
- Frequentist approach to objective probability will fail.
There is already some pressure on the Commonplace Thesis: it is now widely accepted that probabilistic explanation is legitimate, random sampling doesn't need genuine chance, and that frequentism is in serious trouble.