You know, that post is somewhat annoyingly titled. 0 and 1 are probabilities by the common definition of “probability”, but defining “probability” such that 0 and 1 are not probabilities results in a system which is also consistent and useful.
You know, that post is somewhat annoyingly titled. 0 and 1 are probabilities by the common definition of “probability”, but defining “probability” such that 0 and 1 are not probabilities results in a system which is also consistent and useful.