Two Faces and Three Masks of Probability

The concept of probability has fascinated and puzzled numerous philosophers since its inception three and a half centuries ago. Mathematicians and scientists too, whether basic or applied, have often taken part in philosophical discussions on probability. Notwithstanding such discussions, which have been numerous and often spirited, there is still considerable divergence of opinion concerning the interpretation of probability. (See e.g. du Pasquier 1926, Fine 1973.) This is probably due to the fact that the choice of interpretation is largely a matter of philosophy. Not that philosophy is necessarily inconclusive, but it does colour all thinking on fundamental questions.