As part of the ongoing attempt to fully naturalize the concept of human being--and, more specifically, to re-center it around the notion of agency--this essay discusses an approach to defining the content of representations in terms ultimately derived from their central, evolved function of providing guidance for action. This 'guidance theory' of representation is discussed in the context of, and evaluated with respect to, two other biologically inspired theories of representation: Dan Lloyd's dialectical theory of representation and Ruth Millikan's biosemantics.