Final answer:
Functionalists define mental states in terms of functions to avoid the problem faced by Type Identity theorists.
Step-by-step explanation:
Functionalists define mental states in terms of functions rather than identifying them with brain states to avoid the problem that Type Identity theorists face. The problem for Type Identity theorists is the difficulty in establishing a one-to-one correspondence between mental states and specific brain states. Functionalists, on the other hand, define mental states in terms of their function or role in supporting cognitive processes. This allows for greater flexibility in explaining mental states and avoids the challenge of identifying specific brain states for different mental states.