Moving from animals to another example: If you are a half-bald person you do not belong to the set of bald people with probability 0.5. Probability is a epistemic concept, but the vagueness (fuzzyness) of the concept of baldness is not epistemic, but semantic. No amount of information makes you more or less bald. Therefore, for fuzzy concepts, there is no probability of membership of a set, but a degree of membership of a set. Which is again a number between 0 and 1, but it is not a probability. There is actually a very unpopular logic which is based on this notion of fuzzy sets: Fuzzy logic. It’s logical constants behave different from their equivalents in probability theory. E.g. commonly: A and B = MIN(A, B); A or B = MAX(A, B).
Moving from animals to another example: If you are a half-bald person you do not belong to the set of bald people with probability 0.5. Probability is a epistemic concept, but the vagueness (fuzzyness) of the concept of baldness is not epistemic, but semantic. No amount of information makes you more or less bald. Therefore, for fuzzy concepts, there is no probability of membership of a set, but a degree of membership of a set. Which is again a number between 0 and 1, but it is not a probability. There is actually a very unpopular logic which is based on this notion of fuzzy sets: Fuzzy logic. It’s logical constants behave different from their equivalents in probability theory. E.g. commonly: A and B = MIN(A, B); A or B = MAX(A, B).