If you read the post, you'll see that Carroll means it in a specific and experimentally precise sense: not that "physics is finished", but simply that we have e

If you read the post, you'll see that Carroll means it in a specific and experimentally precise sense: not that "physics is finished", but simply that we have experimentally ruled out the possibility of interactions beyond the standard model (plus gravity) that are strong enough to affect the physics of everyday life in any measurable way. We absolute expect that there are things we do not know about at all (much less fully understand)! But any new interaction strong enough to have measurable effects on systems at familiar human scales would necessarily have shown up in experimental searches many years ago.