Final answer:
Functionalist philosophy maintains that if a brain in a vat is functioning similarly to how it would within a human body, it continues to possess mental states since the mind is the activity of the brain.
Step-by-step explanation:
According to the Functionalist perspective, mental states are the result of brain functions—essentially, what the brain does in terms of processing information and exhibiting behaviors. If we consider a 'brain in a vat' scenario, as posed by American philosopher Hilary Putnam, a Functionalist would argue that as long as the brain is performing the correct functions and processes that we associate with mental states such as thinking, feeling, and experiencing, the brain would still have mental states. This perspective views the mind not as a separate substance but as activities carried out by the physical brain, analogous to other bodily functions like digestion or circulation. In this hypothetical scenario, if the brain continues to function and process information as it would within a human body, even when placed in a vat and connected to a computer system simulating experiences, the brain would still retain its mental states. Computer thinking might be objected to on the basis that a computer only performs what it is programmed to do, yet the Functionalist might argue that since both brains and computers process information, it could be possible in principle to have computational devices with mental states.