-I wasn't ready to hear it then, but—I mean, probably not? So, for the _most_ part, all humans are extremely similar: [as Yudkowsky would soon write about](https://www.lesswrong.com/posts/Cyj6wQLW6SeF6aGLy/the-psychological-unity-of-humankind) [(following Leda Cosmides and John Tooby)](https://www.cep.ucsb.edu/papers/pfc92.pdf), complex functional adaptations have to be species-universal in order to not get scrambled during meiosis. As a toy example, if some organelle gets assembled from ten genes, those ten alleles _all_ have to be nearly universal in the population—if each only had a frequency of 0.9, then the probability of getting them all right would only be 0.9<sup>10</sup> ≈ 0.349. If allele H [epistatically](https://en.wikipedia.org/wiki/Epistasis) only confers a fitness advantage when allele G at some other locus is already present, then G has to already be well on its way to fixation in order for there to be appreciable selective pressure for H. Evolution, feeding on variation, uses it up. Complicated functionality that requires multiple genes working in concert can only accrete gradually as each individual piece reaches fixation in the entire population, resulting in an intricate species-universal _design_: just about everyone has 206 bones, two lungs, a liver, a visual cortex, _&c_.
+I wasn't ready to hear it then, but—I mean, probably not? So, for the _most_ part, all humans are extremely similar: [as Yudkowsky would soon write about](https://www.lesswrong.com/posts/Cyj6wQLW6SeF6aGLy/the-psychological-unity-of-humankind) [(following Leda Cosmides and John Tooby)](https://www.cep.ucsb.edu/papers/pfc92.pdf), complex functional adaptations have to be species-universal in order to not get scrambled during meiosis. As a toy example, if some organelle gets assembled from ten genes, those ten alleles _all_ have to be nearly universal in the population—if each only had a frequency of 0.9, then the probability of getting them all right would only be 0.9<sup>10</sup> ≈ 0.349. If allele H [epistatically](https://en.wikipedia.org/wiki/Epistasis) only confers a fitness advantage when allele G at some other locus is already present, then G has to already be well on its way to fixation in order for there to be appreciable selective pressure for H. Evolution, feeding on variation, uses it up. Complicated functionality that requires multiple genes working in concert [can only accrete gradually](https://www.lesswrong.com/posts/ZyNak8F6WXjuEbWWc/the-wonder-of-evolution) as each individual piece reaches fixation in the entire population, resulting in an intricate species-universal _design_: just about everyone has 206 bones, two lungs, a liver, a visual cortex, _&c_.