I think an important issue when it comes to all discussions about
ancient civilizations is how to define it. What in your view is the definition of
civilization? Is it just any human culture or does it have some required
characteristic? You mention that the use of shoes may go back very far,
but does this make it a civilization.
Secondly, what in your view causes the rise of civilization?
Thirdly, you suggest that the lost civilization could be more than 40,000 years old
(even if as far as I know no physical evidence of such a civilization has never been found)
The question is then is there in your view an upper limit for the age of a civilization
on this planet. Would it in your view be possible that there are civilizations that
are 100,000, 200,000 or even a million years old and if so what sets the limit?