 McTaggart has comparatively little to say in support of premise (1). (We find McTaggart accepting premise (1) in as early a work as his Studies in the Hegelian Dialectic, section 144.) Roughly, McTaggart’s rationale for premise (2) is that the contents of positions are events. There is real change only if events change, and the only way an event can change is by first being future, then present, and then past, i.e., by changing positions in the A-series. According to McTaggart, an event enjoying qualitative variation across its temporal axis, such as a poker that begins hot and later cools, does not constitute an example of real change, since it is always the case that the earlier part of this event is hotter than the later part of this event. For this reason, McTaggart rejects the account of change offered by Bertrand Russell in his Principles of Mathematics (section 442), according to which something changes just in case a proposition true of it at one time is not true of it when evaluated at a later time. (With respect to any proposition P, if P has some truth-value when evaluated at a time, it is always the case that P has that truth-value when evaluated at that time.)