Description:
<jats:p>We show how probabilities can be treated as truth values in suitable sheaf topoi. The scheme developed in this paper is very general and applies both in classical and quantum physics. On the quantum side, the results naturally tie in with the topos approach to quantum theory that has been developed in the last 14 years by the authors and others . Earlier results on the representation of arbitrary quantum states are complemented with a purely logical perspective.</jats:p>