“The human body did not evolve to be easily understood. “
The numan body NEVER “evolved” and this is my point.
Perhaps you can tell me how the heart “evolved”?
Or how the eye “evolved”?
Oh, but it most certainly did evolve. If you look at the fossil record, you'll see fossil hominids from the last several million years with gradually increasing cranial capacities: chimps have 350 cubic centimeters, Astrolopithicus aferensis 415 cc's (3 million years ago), Astrolopithicus africanus 500 cc's (2.5 milion years ago), Homo habilius 700 cc's (2 million years ago), Homo erectus 850-1100 cc's (1 million years ago), Homo sapiens 1400 cc's (150,000 years ago). Now we don't have enough fossil evidence for human evolution to be able to say what the direct relationships between these species are, but the general trend is very clear.
There's further evidence from genetics. If you look at the chimp genome and the human genome, it becomes very clear that they share a common ancestor (which various lines of evidence indicates lived 5 to 7 million years ago). For example, both genomes contain "endogenous retroviruses," DNA from certain kinds of viruses that splice their DNA into the host's genes. If such a virus infects a germ-line cell (an egg or sperm), the DNA can become a permanent but harmless snip of DNA in the species' genome. It turns out chimps and humans have some of the exact same snips of this viral DNA in the exact same locations in their genomes.