Quote Originally Posted by SiuiS View Post
This is a flawed argument because it assumes subjectivity means all things are equal.

If nothing has any inherent value, then it has the value you give it. It can be demonstrated that the thought chain of "well might makes right is ultimately how this shakes out" leads to people being bad people. Optimally you will behave in a way you want others to behave. Physical might is not the only might, and an understanding of social and psychological mechanisms shows that this is a much more complex process than you imply.

This is the danger of logic. You end up flattening everything out into excessively simplified and meaningless broad strokes. This is why logic is a part of rationality and neither the sole not most important part. You WILL have emotional and visceral reactions. They MUST be accounted for. You CANNOT have a purely logical system because a purely logical system assumes everything works in a clear and thought out manner. People are auboptimal. They do not compile.

Morality makes a difference because if establishes different strata of association and socialization. It allows one to justify some things past the normal intolerance threshold. It allows one to exist as part of a society instead of an individual in a cluster of individuals. And this is likely inherited; other primates have similar functions.
Is roach-squishing murder or not? If humans are animals, then we can behave like animals, as we please, unless you wish to appeal to a human self-interest that transcends animalism by saying that what we can achieve is, in essence, sacred. That human life is sacred. If we're just primates, then morality is just a trick of social organisation, which we can dispense with at our pleasure.