But when biologists finds an insect type with different number of something they will call it a new species. That we don't do that for humans has to do with politics more than anything else, some believe we would discriminate against such humans if we said they weren't really the same species.
> But when biologists finds an insect type with different number of something they will call it a new species.
This comment cannot be answered properly without knowing who the "biologists" are, which insect types we are talking about, and what is going along with the different number of something.
The fact that individuals with four or six fingers are considered to be of the same species has nothing to do with politics, but with the fact that people with "4 fingers" can reproduce (this is the expectation) with individuals with "5 fingers" and "6 fingers" and produce fertile offspring.
Politics comes into play when it comes to, for example, species conservation.
Populations of the same species that have remained isolated from each other for centuries, millennia or more may accumulate due to selection processes, genetic drift or founder effect, genetic and phenotypic characteristics that do not allow individuals from the two populations to reproduce successfully. Fertilization may not occur, the progeny may show morphological abnormalities, or the offspring may not be fertile. But the above may occur in, say, 20 percent, 50 percent or 90 percent of cases, and for any of these percentages the existence of a new species, variant or subspecies can be argued.
Should the two populations be protected since they are (or are not) different species?
Then defect is no longer intelligible. And yet, we can determine if a heart is defective, because we know the function of a heart, we know how that function composes into the telos of the organism (which is what transmits the function to organ, so to speak). Thus, any modification of the heart, certainly one that we see has ill effects for the organism, is a defect.
It is clear that a human being who is sterile, or one who cannot move about, is in some sense a defective specimen, as these deficiencies impede the realization of human telos. (If you deny telos, then truly nothing is intelligible. Not only does the notion of defect no longer make sense, not only are biology and biological function impossible and anatomy made unintelligible, but even efficient causality is made unintelligible and science impossible, as the very fact that an effect follows from a cause, that is is not arbitrary, presupposes telos.)
