Indeed, I didn't remember that Chamlers was literally building his argument around the "why?"... But he does.

This reduces to the intractable mystery of existence. A more interesting question would be, as usual "how".

There are serious attempts at this, coming from both neuroscience and physics (e.g. for the latter https://pubs.aip.org/aip/adv/article/15/11/115319/3372193/Un... )