I'm only half a layman, but I know that Brian Green (maybe others?), have put forward the idea that 11 dimensions do exist, it's only that they are "curled up" and so small that we can't (yet) observe them, analogues to how a wire might appear form afar, flat, but as you move close you see it's actually a cylinder, Greens own example.
And why did they propose it, other than to explain why these extra dimensions are not observed in nature, thus patching up a model with a falsified prediction?
Today's post, Timeless Identity was originally published on 03 June 2008. A summary (taken from the LW wiki):
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