The philosophy of mind has emerged as a field of philosophy in its own right, due to the convergence of issues raised in more traditional areas of philosophy, such as metaphysics, epistemology, and ethics.
Some questions asked by philosophers of mind reveal these origins. One might ask: Are mind and body one substance?; Does mind depend on the body?; Is 'mind' identical with 'body'? These questions may lead to others: Do humans actually make free choices, or are all human acts physically determined? As well as physical states, we have mental states and many of the latter relate to each other. For example, individuals have beliefs, desires, and feelings about other mental states, i.e., about concepts. When talk turns to such intentional states or propositional attitudes, further questions arise. Do only humans have intentionality? Must any account which attempts to explain our actions consider intentionality? Or can physical events (brain and body processes in interraction with the physical environment) wholly explain our actions?
Because of the nature of these questions, it becomes apparent why the philosophy of mind might cross over into cognitive science. Cognitive science, after all, tries to answer many of these same questions.