Kaichos Man writes:
Eyes, lungs, retractable claws and all manner of mind-numbingly complex features all become the result of genetic copying mistakes and fluctuations in the environment.
And that's where "the observed" parts company with "the inferred".
Does mutation create a new species? Yes it does. It is observed. Does it create an eye? No. Not in a gogillion years, in a million different universes at once.
So, it's impossible for, say, a lizard to develop, say, a cecal valve?