> Of course you could have had an intelligent society in the past
> without leaving traces that we would find.
Not if the evolution of intelligence involves using tools. There is a
complete lack of arrowheads, stone axes, and other such artifacts in the
geological strata dating back to the era of dinosaurs.
Mark Crosby writes,
> there is a story I've mentioned before ... by Amy Thomson,
> _The Color of Distance_ (11/95), that examines an alien species
> (on another planet) called the Tendu that have evolved a mostly
> non-mechanical but highly advanced biotechnical civilization.
> The Tendu did have a world-wide civilization but their artifacts
> were all bio-degradable and would have left no traces for future
> investigators had they become extinct or 'transcended'.
Just because something is degradable doesn't mean it will degrade.
Wood is bio-degradable, but there is plenty of petrified wood.
Insects are bio-degradable, but entire insects are preserved in amber.
Leaves are bio-degradable, but there are fossilized leaves. Even if
they did use bio-degradable materials, there would be lots of fossils.
A world-wide civilization would require large-scale structures such as
mines, harbors, canals, pipelines, and so forth, which would definitely
leave some trace. Besides, the concept of "biodegradablity" is an
advanced concept that they would only arrive at after a long process of
evolution. When they first started using tools, they must have just used
whatever came to hand.
I think the D. Sapiens scenario requires the intelligent dinosaurs to be
confined to one small area; perhaps because the rest of the world was
too hot and swampy for civilized life. If they lived on an island near
one of the poles, and if this island is now submerged (or was destroyed
when the intelligent dinosaurs blew themselves up), then there would
be no traces. But this seems highly unlikely to me. If they reached a
level where they could transcend, or blow themselves up, then they
could also colonize the rest of the world. But apparently they didn't.
So we arrive back at the Great Filter problem. The dinosaurs lived on
earth for millions of years, but never evolved into tool-using creatures.
Why?
Terence McKenna has suggested that when our ancestors discovered
psychedelic mushrooms, that stimulated them to start thinking, talking,
and using tools. That was when they broke through the filter and
started making progress. Without mushrooms, we could have been
stuck in an evolutionary cul de sac for eons, like the dinosaurs.
Lyle