Now I'm going to try and argue for a third alternative that's much more illuminating than either of those, and to put this into perspective, let's imagine that a Martian came down to Earth and found a ruined civilization.
现在我给你们讲讲第三种可能性。 这种可能性比前面的两个提问会更有启发性。 让我们换个角度， 想象一个火星人来到地球 并发现了一个被破坏的文明。