When a pragmatic dimension is incorporated, functionalism contradicts reductionist interpretations because it may be impossible in practice to specify relevant functional roles using only the resources of lower-level theories
The view that complex things can be completely explained by breaking them down into their smallest, simplest parts—like explaining a person entirely through their atoms.
functional roles(as used in philosophy of mind)
The jobs or purposes something is designed to do, like how a calculator's functional role is to perform math—in this context, the information-processing tasks the brain performs.
functionalism(Philosophy of mind; distinguished here from representationalism)
The view that mental states are defined by the causal roles they play in a cognitive system — their actual, potential, or typical causal relationships.
Others have argued that functionalism best suits non-reductive physicalism in the following sense: It maintains the naturalist’s intuition that there is unity among the underlying property-realizers which are all ultimately physical; hence, token identity theory is true. Nevertheless, it opens the possibility to accommodate the threat of multiple realizability in a particular way: Functional kinds can be multiply realized, and, hence, they can be regarded as being distinct from the lower-level p