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Eileene decided to engage me at 2am last night in discussion about time travel and whether closed loops therein are paradoxical. I still don’t know what set her off, but she ended up furious, and the insomnia I was already fighting won out. So I might as well start writing.

The thing is, she’s practically got it, the whole thing. She recognizes that a closed-loop scenario has no discontinuities. (No discontinuities, that is, other than the point of arrival in the time stream and the point of disappearing from it to travel back in time. Those could be considered discontinuities, but we’re presuming time travel exists in the first place, and that they map cleanly either to one another or to the ends of an object’s path traveling backward in time, so they don’t count.) No physical laws are broken, other than those broken by the presumption of time travel itself. And yet she insists that “objects from nowhere” are illogical.

They aren’t. They are merely surprising and counter-intuitive. Living in linear time, we’re used to objects having a beginning and end, and the need to “be created” at some point in order to exist at all. But in the wilder universe of time travel, that doesn’t have to be so. She’s at the conceptual equivalent of the 19th century geometers who, in attempting to prove Euclid’s parallel postulate by contradiction, instead created consistent geometrical systems equally valid with Euclid’s. Yet many of these mathematicians would get a certain distance into their work and declare, improperly, that they’d found a contradiction, when they’d merely found something deeply counter-intuitive, like parallel circles. Once younger mathematicians decided to take geometrical elements like circles and lines for what they were in these newer geometrical systems, rather than simply presuming these elements must behave like analogous elements in Euclidean geometry, they quickly turned up fully-conceptualized systems in which the startling properties of non-Euclidean geometry were not only true, but intuitive: circles lying parallel to one another when drawn on the surface of a sphere like latitude lines, or triangles with interior angles adding to less than 180° when drawn on a wobbly, saddle-shaped surface.

Once you demonstrate to your satisfaction that there’s no actual contradiction in a conceptual system, it’s time to accept that it makes sense, albeit on terms that we do not regularly encounter in ordinary life. And if you can accept that, you can make great discoveries.

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