No other animal has any moral or legal prohibitions against rape or murder, and they seem to survive just fine--at least no species has been known to go extinct due to rape, murder or theft among their own species. Evolution obviously doesn't explain the moral disapproval or legal prohibitions that humans have against rape, murder or theft.
Exactly, other animals don't need to have it written out in stone to not kill each other - it's written into their nature. Ofc you will have exceptions, but the whole reason why animals can live in packs together is because they co-operate. Why do they do this? Because it is behavior that promotes survival and makes them more robust as a unit. If animals couldn't co-operate and have their own social system, all mothers would kill their newborns for food and all species would die.
Our morality is the human manifestation of this same mentality. How much or little evolution itself plays is an open question. I don't know, and that was never my point.
My point was we have set out morals not because they are objective facts, but because they help us survive and live together more safely in a community. If you can't understand that, then this is pointless to discuss.
And I asked: What would be a context where it would be moral for an intelligent, competent adult [e.g., of another species on another planet] who can discern moral from immoral acts to rape a 4-year-old child [of their own species]?
Obviously, if you can't think of any circumstance in which an act would be moral, then you have no rational reason to conclude that the morality of the act is relative to circumstances.
Are you seriously going to make me answer this?
Fine. I question your own morality if you're sick enough to ask me (a human being who
does see rape as immoral) this, but if you insist:
Another planet entirely, huh? Okay then! That means they might live in an environment completely different to us, and thus might evolve completely differently and form completely new behaviors. Let us call this species "Hypotheticus".
The Hypotheticus is a species where only children between the ages of 3 and 6 can produce offspring, and their bodies are set up in such a way that they must remain still in order to successfully produce offspring. They are not old enough to mentally consent, but one adult Hypotheticus is given a dilemma where it must reproduce non-consensually (or "rape") another one or else everyone it knows will die (because reasons). Oh yeah, the Hypotheticus also doesn't feel pain, so there is no suffering involved.
If this isn't good enough - and you still say rape is still immoral here - then it might very well be a situation where asking for a hypothetical where species forcibly rape other members against their will is against the very idea of prosperity and safety. It would be like asking me to think of a scenario where it would be moral for a random species to kill its own children when they're born - it's just not viable, because that would extinguish the species and they wouldn't survive.