natural selection cannot be practically applied to humans, but artificial selection can, and should, be used
That is rather a vague and offensive statement Crowbar.
Scientific advance should be used to give all people as good a life as possible. Only the person involved can make the decision about whether they should live or not, and hopefully they will be given the opportunity to have a good a life as possible and so will want to live. I don't think these biologist’s views bare much weight Crowbar. I don't think we have anything like the depth of understanding that would be required to make the decisions involved in "artificial selection".
They're optimized to survive. And from an evolutionary perspective, which is what I'm discussing as was clear with my initial post, that is all that matters.
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Humans like to see themselves as the peak of evolution.
We are a bit of an evolutionary wonder. It seems strange that you argue that at the same time that we are not at the peak of evolution and that evolutionary pressure no longer effects us, may be we have "out grown" it to some extent, but then what does that tell you? The old fitness function is not comprehensive enough anymore - survival. So arguing in those terms is a bit pointless unless you are talking about simpler organisms.