This document outlines several theories regarding the relationship between the mind and the physical brain/body: 1. Behaviourism views mental states as dispositions to behave in certain ways. 2. Identity Theory claims mental states are identical to specific brain states. Advances in neuroscience support this view. 3. Functionalism defines mental states as functional roles that relate inner states to behaviors, arguing this allows for the possibility of non-biological entities like aliens or AI having minds. 4. Eliminative Materialism takes the radical position that mental states do not exist at all and are merely illusions caused by habits of speech.