They must have been much cleaner than us then - no pollution or waste. Seriously, there would be bones and buildings. However, 'The Science of the Discworld' would not be a book I could easily disagree with given the astrophysics behind the four elephants and giant turtle.
I've seen this theory around, and as I recall, in most iterations the theory includes a very, very long span of time between that ancient life/civilization, and us -- time enough, for instance, for the geological processes of the Earth to tear apart and/or bury most relics.
Do I buy it? No. I can certainly appreciate, and look with interest at, the speculation that life might have come about on more than one occasion, and that fish might have come to land more than one time (certainly those speculations are true to the entire theory of evolution).
But for life to have gotten as far as making a previous civilization? That's harder to swallow. (That said, as a good fan of sf and f, I love it!)
(Who can say whether such a previous life form had bones at all? Maybe they were similar to jellyfish?)(And intelligent jellyfish would generally be unable to manipulate hard matter enough to build temples, etc. So they lived in burrows in the ocean floor, and left no buildings... It could happen!)
(And, just for entertainment value, I will note that a moment ago, looking at the list of recent postings on the home page, I noted that the mention of Dave's last post was curtailed to "Fish may have evolved to live on..." -- and, my mind, being beyond my control, finished that with "...cheeseburgers." Well, that's just how I am...)
(another) Dave
