ABSTRACT
Time travel involves insuperable paradoxes of a broadly logical sort, and so is metaphysically impossible. In any time travel story people have to distinguish two frames of temporal reference. One frame is based on the time travellers themselves; time as measured by the watches they wear, or by their mental and biological processes. The other frame is that of Earth. This two-dimensional model of time is due to Meiland, who explores its ramifications in detail. In the light of The Big Loop the big bang might not be entirely inexplicable, but this quibble aside, Lewis seems to have a point. According to quantum theory it is possible for complex objects to appear from nowhere, random distillations from the quantum foam; classical thermodynamics carries a similar implication. It may be that the Compound Presentism, has the resources to provide a more solid foundation for claims about the past, and hence of travel to other times.
