https://astralcodexten.substack.com/p/against-ice-age-civilizations

There's a good debate about this on the subreddit; see also Robin Hanson and Samo Burja.

You can separate these kinds of claims into three categories:

1. Civilizations about as advanced as the people who built Stonehenge

2. Civilizations about as advanced as Pharaonic Egypt

3. Civilizations about as advanced as 1700s Great Britain

The debate is confused by people doing a bad job clarifying which of these categories they're proposing, or not being aware that the other categories exist.

2 and 3 aren't straw men. Robert Schoch says the Sphinx was built in 9700 BC, which I think qualifies as 2. Graham Hancock suggests "ancient sea kings" drew the Piri Reis map which seems to depict Antarctica; anyone who can explore Antarctica must be at least close to 1700s-British level.

I think there's weak evidence against level 1 civilizations, and strong evidence against level 2 or 3 civilizations.