Hey so I'm actually writing a paper on the biological basis of morality and am taking an evolutionary standpoint on it. So my premise is based upon the fact that all living beings have the intrinsic need to survive and reproduce, which is what natural selection is based upon. Also, it has been researched that species (using the definition of organisms that can breed with each other and produce viable offspring) care for each other and co-operate with each other to ensure the survival of their own species. Now I believe that this would lead to one objective moral truth that we ought to care for the well being of our species. I know this commits the is ought fallacy but I believe it can be overlooked in this case since this behavior of survival and reproduction can be observed in all species that we know of to date. Do you think this Is a fairly viable standpoint to take or am I missing something essential?

When you say that "species...care for each other and co-operate with each other to ensure the survival of their own species," I take it you're referring not to all species (including all plants, all microbes, all invertebrates, etc.) but only to those species whose members care for each other and cooperate with each other, which may be a minority of the species that exist.

Anyway, you ask whether something like the following argument is "fairly viable":

1. The members of all species [of the restricted kind referred to above] act so as to promote the survival of their own species.
2. Therefore: We humans ought to act so as to promote the survival of our own species.

As you seem to recognize, the argument isn't logically valid: The premise doesn't logically imply the conclusion. But the argument can be made logically valid by inserting a premise, such as

P. We humans ought to do what the members of all species [of the restricted kind referred to above] do.

One problem is that P itself is highly doubtful. The members of all species [of the restricted kind referred to above] engage in at least some of these behaviors: killing each other, eating their own offspring, killing the offspring of competitors, consuming their food supply until they're threatened by starvation, using physical violence to secure mating opportunities, and having sex by overpowering resistance. We humans are no exception. Yet you wouldn't argue that we humans ought to do any of those things.

In general, I think that arguing from biological facts to moral principles is an unpromising strategy.

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