From what little of Denton’s I’ve read(which, full disclosure, is one paper on early protein evolution) is saying some apparent adaptations aren’t really adaptive(that this is not why they emerged in the first place, as in gradually under selection), rather they’re sort of built into the fundamental physical constants and laws of nature.
So he’s not really challenging the fact that evolution occurs, nor common descent, nor even that the evolutionary process is blind to the future, rather he’s opposing/challenging some kind if view of evolution which (I think this is how he sees it) says that certain structures owe to a combination of chance historical contingencies, and gradualism+natural selection.
Going from memory here he says in one paper of his I’ve read on early biochemical evolution near the origin of life, that he thinks certain protein structures with certain functions were sort of “built into” the fundamental properties of amino acid polymers and the chemistry that gives rise to them.
He suggests that because of the physical processes that give rise to amino acids, there are going to be certain inherent biases in the frequencies of which amino acids are produced.
And then because you end up with a biased distribution in the frequencies of certain amino acids, these distributions have a bias towards yielding particular short peptides, and these peptides with their amino acid biases are going to have biases towards adopting particular secondary structures(say, an overabundance of glycines and alanines yield some secondary structure much more often than others), and these particular secondary structures are going to have biases towards assembling into certain even larger tertiary structures. And these in turn are going to be biased towards particular functions(such as nucleotide binding or something along those lines). And so on and so forth.
And at least with respect to early biochemical evolution, it doesn’t appear to me he’s talking total nonsense. There does appear to be evidence of various inherent biases in the kinds of chemistry that can happen, and what structures are more likely to emerge from that. But there are also some considerable open questions here.
The real question is how strong are these putative inherent biases, and do they result in the sort of extreme “funneling” effect, for lack of a better term, that he imagines where they basically lead to the same thing every time? That’s where the chain unhinges for me, because there’s just not any good evidence for that.
So he sort of imagines that the laws of physics are somehow “programmed”(paraphrasing) to give rise chemistry of a particular type under the right conditions, and that chemistry gives rise to life of a particular type, which makes him expect that if and when life arises elsewhere in the universe, it’s going to be pretty much the same everywhere. And from these very similar initial conditions, IIRC a genetic code like ours is going to evolve every time yadda yadda yadda, one thing funnels/is biased towards another, and then basically the same thing all the way to human-like primates.