Faster Than Light

  title={Faster Than Light},
  author={Robert Paul Geroch},
It is widely believed that relativity -- both special and general -- requires that no physical signal travel at a speed faster than that of light. For instance, the assumption that there could be superluminal signals in relativity gives rise to well-known paradoxes. We suggest that this situation is not nearly as dire as it appears at first sight. Indeed, we shall argue that relativity is virtually as viable and self-consistent as a physical theory in the presence of superluminal signals as it… 
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