Are aliens FTL humans?

What do you think of the following scenario*? Aliens are future humans who discovered faster than light travel. They propagated throughout the universe. In so doing they travelled back in time, to our time, or even earlier times.

*I read this in a popular space opera novel. It may have been Charles Stross or Alastair Reynolds. But I am not certain.

 

Thanks for the news article. Here's another thought - also thunk by someone else first. If aliens are future humans who flew back in time to teach us about pyramids so we can advance and eventually become them, travel back, and teach our ancestors ... and round and round ... *where* did the idea for pyramids come from in the *first* place?

 

All grammar is relative?