<p>There are various theories in the philosophy of mind/cognitive science of what kinds of knowledge, or information carrying mental states, constitute our mental concepts. Such knowledge is used in higher acts of cognition such as in categorization, induction, deduction, and analogical reasoning when we think or reason about the extension of the concept. While most concept theories have primarily focused on concrete concepts such as `chair,' `table,' and `dog,' I take such modern theories and apply them to abstract moral concepts such as `virtue,' `right action,' and `just.' I argue for a new overall pluralistic theory of moral concepts, combining several theories of concepts. This pluralistic view differs from, for example, Ayer's non-cognitivist theory that contends that our moral concepts are constituted by or just are emotions and desires. Finally, I draw further philosophical implications my conclusion may have for applied ethics, normative ethical theory, political philosophy and meta-ethics.</p> / Dissertation