My apologies for my tardiness, I am trying to answer questions properly, as this is one of my favorite subjects of study
Now, there’s a whole idea called “multiple realizability”, which basically states that, "for any given exhibition of a mental(nonphysical) state, there can be multiple corresponding brain states. So let’s say we’re both happy, and we’re both acting happy, so a guy looks at us both and says, “let’s look at the state of the neurons in both those brains and see if they’re the same, since they’re both acting the same”. Then when he looks, he sees totally different concentrations of neurotransmitters between my brain and yours, then tries to assert that because the brain states are different, that there is no relationship, (or idenity, or reducability) between the brain states and the mental states. Therefore, there is still a dualism of physical and non-physical.
Then the next step for the materialist is to say that the identity is in the functional role that the brain state plays. Then you start saying that the identity between two brains is not in the placement of the neurotransmitters, as they can clearly be different, but that it’s instead in the functional role. The brains serve an identical function, and are defined in terms of the functional role that they play. (name removed by moderator)ut—>brain—>output. Dog dies—>brain state—>exhibition of behavior consistent w/ a mental state of “sadness”. In this case the differences in the locations of the neurotransmitters between your brain and mine are irrelevant. Both of us have the same (name removed by moderator)uts and outputs, and our brains therefore play the same functional role, but the neural states are still different, but that’s ok because we’ve dealt w/ the multiple realizability problem by pointing to a functional identity.
In philosophy of mind, there are no two more important concepts than reductionism, and functionalism.