Final answer:
Aristotle's insights argue against ethical relativism by presenting an intrinsic purpose for humans—the achievement of eudaimonia through virtues, implying an objective moral basis accessible through reason.
Step-by-step explanation:
Aristotle's insights concerning human nature offer a counterargument to the claims of ethical relativism, positing instead that humans have an intrinsic purpose or telos, which is to achieve eudaimonia or flourishing through the cultivation of virtues. This view implies an objective basis for ethics that can be understood through reason and observation of the natural world, as opposed to ethical relativism which suggests that moral norms are solely determined by cultural practices and subjective perspectives. By identifying the function or purpose intrinsic to humans, Aristotle provides an alternative to relativism that seeks universal principles relevant to all humans for guiding moral actions.