This document discusses several philosophical theories of mind: 1. Behaviourism views mental states as dispositions to behave in certain ways. 2. Identity Theory claims mental states are identical to brain states. Advances in neuroscience support this view. 3. Functionalism defines mental states based on their causal relationships and functions, not the underlying physical implementation. This allows for the possibility of artificial intelligence. 4. Eliminative Materialism argues that talk of mental states should be eliminated and reduced completely to physical descriptions of the brain. It claims beliefs and desires do not truly exist.