 One of the most discussed aspects of Collingwood’s philosophy of history is his claim that the historical past is not retrodicted but re-enacted. The task of historians is not to establish that a past event had to happen in the past, in a way analogous to that in which a scientist predicts that a solar eclipse will happen in the future, but to re-enact the thoughts of historical agents. Collingwood claims that when historians re-enact the thought of an historical agent, they do not re-enact a thought of a similar kind but the very same thought as the agent. This claim has often been regarded as counterintuitive because to say that the thought of the agent and that of the historian are one and the same appears to presuppose that there is only one rather than two numerically distinct acts of thought: that of the historian and that of the agent. Collingwood’s point, however, is that, since what the historian re-enacts, i.e., the propositional content of thought (he refers to this simply as thought) is distinct from the acts of thinking (he refers to these as sensations/feelings), the criterion of identity that is normally applied to individuate acts of thinking does not apply to thought (IH 1993: 287). Acts of thinking are individuated and distinguished from one another by adopting spatial criteria. By contrast thoughts (i.e., propositional contents) are individuated on the basis of purely qualitative criteria, so that if there are two people entertaining the (qualitatively) same thought, there is (numerically) only one thought since there is only one propositional content. For Collingwood, if Jane and Jim recite the practical syllogism “All men are mortal, Socrates is a man, therefore Socrates is mortal” they entertain one and the same thought. By the same token, a historian who re-enacts the thought of a past agent entertains the very same thought as the historical agent: