This viewpoint suggests that mental states are accounted to solely by their functional role, by their causal relations to sensory input, behavioral output, and other mental states.

Thus, any being that functionally behaves like a human must have conscious experiences identical to a human's.

Essentially, this viewpoint posits that what makes something a mental state is causal relations to sensory input, behavioral output, and other mental states.

Therefore, any entity capable of fulfilling these roles should possess the same mental experiences, regardless of the specific material composition of the brain or body.

A classic example illustrates this concept involves pain.

According to functionalism, what matters about the experience of pain is not that it's caused by a particular type of neural activity, e.g.

C-fiber stimulation in humans, but rather that it serves specific functions like producing avoidance behavior, triggering emotional responses, and motivating decisions to protect the body.

Thus, if an alien species or any artificial intelligence system could functionally replicate these patterns of responses and interactions, Functionalism asserts that they too would experience pain, even if their neural architecture is vastly different.

This framework challenged the idea of P-zombie because it insists that any being that behaves indistinguishably from a conscious human would necessarily have the same conscious experiences.

According to functionalism, consciousness isn't a mythical property separate from physical processes, but is a result of the functional role that this process fulfills.

Critics of the P-zombie argument, like Daniel Dennett, leveraged functionalism to argue that P-zombies are conceptually incoherent.

If a hypothetical being behaves and reacts to the world in the same way a conscious person does, then by functionalist account, it is necessarily conscious.

Dennett's famous intentional stance further supports this, suggesting if treating something as a conscious agent reliably predicts its behavior, then it should be considered a conscious agent.

Moreover, functionalism provides a theoretical basis for understanding artificial intelligence and the consciousness of non-human entities.

For instance, if a computer program could replicate all the functional aspects of human cognition, many functionalists would argue that the program could be considered conscious.

Functionalism presents a compelling challenge to P-zombie thought experiment by denying that there could be an entity in every way like a conscious human but lack consciousness itself.

Instead, it emphasizes that mental states are fully defined by the patterns of interactions and behaviors associated with them.