Philosophy of Mind
Token Materialism
and the Mind-Body Problem
A position paper on the mind-body problem evaluates Dualism, Functionalism, Type Materialism, and Token Materialism against empirical and conceptual evidence. The analysis defends Token Materialism as the framework best able to account for multiple realizability while remaining open to non-human minds.
The Position
Token Materialism holds that a functional state, whether a thought or behavior, results from a brain state, and the same functional state can be realized by different kinds of brain states (Smart 2017). The framework neither discounts new evidence that may shift the position, nor treats the mind as something separate from the physical processes that produce it.
The argument develops by examining each competing position, identifying its strongest objections, and showing why Token Materialism survives them while the alternatives do not.
Mental states are physical
Materialism rejects the Cartesian division between mental and physical substance. Thoughts, emotions, and behavior are manifestations of physical phenomena in the brain.
Function over structure
The same mental state can arise from different physical configurations. What matters is the functional role the state plays, not the specific neural circuitry realizing it.
Mapping the Theoretical Landscape
Each position answers the same question differently: how do mental states relate to physical states?
Dualism
Descartes; Property Dualism
The mental and the physical are two distinct phenomena. Modern property dualists allow interaction but maintain distinct properties.
Central Objection
Princess Elisabeth of Bohemia raised the interaction problem: if mind and body are different substances, how can they interact at all? No currently available evidence describes how immaterial and material substances would interact.
Functionalism
Behavioral causal relations
Mental states are defined by their causal relations to behavior, stopping short of identifying them with their neural realizations (Smart 2017).
Central Objection
By treating behavior as the sole representation of inner states, Functionalism cannot account for cases like mental illness, where behavior may not accurately reflect a person's true mental state.
Type Materialism
Identity Theory
Thoughts and actions are manifestations of neural states. Each mental type corresponds to a specific neural type.
Central Objection
Faces the multiple realizability problem. Two processes with the same function would not count as the same mental state if their neural patterns differ. The framework cannot accommodate functionally equivalent states in different brain configurations.
Token Materialism
Defended position
Mental states are physical, but a single functional state can be realized by multiple distinct physical processes. The same function classifies as the same state regardless of underlying mechanism.
Central Objection
Imagining the combinations of neuronal firing that produce specific thoughts can be difficult, but difficulty of grasp does not exclude existence.
The Multiple Realizability Problem
A biological arm and a prosthetic arm can serve the same function. If function determines the state, why should the substrate change the classification?
Human neural process
Pain registered through the human nervous system
Same function
“Pain”
Non-human system
E. coli sensorimotor system; alternative biological substrates
Type Materialism cannot extend
Tying mental states to specific neural types restricts the framework to species with those neural types. Animals without comparable circuitry are excluded by definition rather than by evidence.
Token Materialism accommodates
Different physical processes that achieve the same function count as the same state. The framework remains open to mental states in animals, atypical brains, and any system meeting the functional criteria.
What Counts as a Mind?
Binary categories exclude humans with psychological disorders, biological mutations, and cognitive differences. Token Materialism reframes the mind as branches and buckets rather than a sliding scale.
Criterion
Pain
Capacity to register and respond to noxious stimuli
Criterion
Emotion
Affective states shaping behavior over time
Criterion
Communication
Signal exchange directed at another agent
Criterion
Conscious behavior
Goal-directed action under apparent awareness
Test case
A dog
Winces when stepped on. Wags when content. Signals hunger to a familiar human. Walks to a water bowl when thirsty.
Test case
A comatose patient
Brain activity persists. Direct expression of pain, emotion, communication, and conscious behavior is absent, but the capacity for those characteristics often remains.
Test case
A human with nervous system damage
May not experience pain in the typical way, but the other criteria remain accessible. The framework respects mutation and variation rather than excluding it.
Conclusion and Takeaways
Function classifies the state
Token Materialism keeps the materialist commitment without forcing identical neural realization. The same function classifies as the same state regardless of substrate.
Open to other minds
The framework leaves room for non-human minds, atypical brains, and future evolutionary variants without abandoning physicalism.
Vocabulary is not metaphysics
Colloquial talk of mind and body as separate is a residue of dualism. The grammar does not establish two substances; it reflects the difficulty of describing physical processes from the inside.
Key Takeaway
Mental states are manifestations of physical processes, but the mapping from function to substrate is many to one. Token Materialism preserves the materialist commitment and admits the variability that the evidence already shows.
Same function, different realizers
