There are two readily apparent problems with the axiom, “humans act.”
The first is the definition of human. Are babies, cavemen, or chimps considered humans? What about a mentally impaired person? If we restrict the definition of human to be a certain group, that restriction needs to be justified within the framework or else the foundation is missing.
The second is the meaning of act. It can be defined as “a conscious choice to remove uneasiness.” The problem then regresses to uneasiness (or whatever negative term you insert). If I consciously choose to hurt myself, how am I reducing uneasiness? You can broaden ‘uneasiness’ so that hurting myself is actually reducing mental anguish from having to deal with your argument. Doing that then reduces the usefulness of the term to zero because it becomes circular!
If everything I consciously do is inherently removing uneasiness, and the definition doesn’t leave the option of a conscious non-act, then we can’t derive anything useful from it because the posited premises force the desired conclusion.
What insight is there from the idea that human action is human action?