- No one denies that time and space are different; and it is easy to catalog differences between them. I can point my finger toward the west, but I can't point my finger toward the future. If I choose, I can now move to the left, but I cannot now choose to move toward the past. And (as D. C. Williams points out) for many of us, our attitudes toward time differ from our attitudes toward space. We want to maximize our temporal extent and minimize our spatial extent: we want to live as long as possible but we want to be thin. But these differences are not very deep, and don't get at the essence of the difference between time and space. That's what I want to understand: I want to know what makes time different from space. I want to know which difference is the fundamental difference between them.
- I will argue for the claim that (roughly) time is that dimension that plays a certain role in the geometry of spacetime and the laws of nature. (In this paper, then, I focus on what is distinctive about time, and say little about what is distinctive about space.) But before giving the argument I want to put my question in slightly different terms. Instead of asking, 'what makes time different from space?,' I want to ask, 'what makes temporal directions in spacetime temporal, rather than spatial?'
- After rejecting some bad answers to this question I'll present my view.
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- Blue: Text by me; © Theo Todman, 2018
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