[QUOTE=Chief Pedant]
We are able to control whether or not we want to reproduce at all, for instance, even if the genes we contain are highly successful modifications. We can also control and direct the external circumstances which would otherwise affect descent. A human may no longer need to be smarter faster or stronger to have a reproductive advantage, for example.
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Ultimately, doesn’t this mean that the “circumstances” you describe are very different now than in the past?