There is something peculiar about the way we talk about the brain.

We describe the heart in physiological terms. It contracts and pumps blood. We describe the kidneys in physiological terms. They filter blood and regulate the balance of water and electrolytes. We describe the lungs in physiological terms. They exchange gases.

But when we reach the brain, something changes.

Suddenly an organ does not merely exhibit physiological activity. It thinks. It remembers. It decides. It recognizes faces. It processes information. It represents the world.

Why?

The answer seems obvious: because these are precisely the things the brain does. But this answer already contains the problem.

Where does cognition come from?

We do not observe cognition in the brain in the same way that we observe electrical potentials, neurotransmitter concentrations, blood flow, or patterns of neural activation.

Consider memory. How do we know that somebody remembers something?

We ask the person. We present something previously encountered and observe whether it is recognized. We measure responses, reaction times, errors, verbal reports, and behavior. From such observations we conclude that the person remembers.

The same applies to perception, decision-making, learning, and problem-solving. Our epistemic access to these phenomena begins with the individual: with what a person says, does, distinguishes, recognizes, or reports.

We collect such phenomena under the term cognition.

In this sense, cognition is not an additional object that we discover alongside neural activity. It is a category under which we describe and organize certain capacities and behaviors of an individual.

Now imagine simply leaving the word cognition out.

Nothing in the organism would change. Neurons would still fire. Networks would still oscillate. The person would still recognize a face, answer a question, or find the way home.

We would merely have omitted one of our descriptions.

From description to thing

The difficulty begins when we forget this.

First, we observe an individual behaving in a particular way and describe this as remembering, deciding, perceiving, or thinking.

Then we investigate the nervous system and discover physiological processes that systematically correlate with these observations.

So far, there is no problem.

But then a subtle transformation occurs. The psychological description is transferred into the brain. We begin to say that the brain itself remembers, decides, perceives, computes, or represents.

A description of the individual has become an apparent property or function of one of its organs.

And once this has happened, philosophy and cognitive science face a mystery of their own making: How does neural activity produce cognition? How does information processing produce experience? How does a functional state become a conscious state?

The linguistic duplication has quietly become an ontological duplication.

But doesn't the brain cause behavior?

A natural objection seems decisive.

Suppose we electrically stimulate a particular brain region and the person's perception or behavior changes. Does this not demonstrate that neural activity causes psychological activity?

No.

What the experiment demonstrates is a causal intervention in a living individual.

The stimulation changes the organism. The consequences of that intervention can subsequently be investigated in different ways. Physiologically, we may describe altered neural activity. Psychologically or behaviorally, we may describe an altered perception, report, decision, or action.

These are not two events between which the experiment has discovered a mysterious cross-level causal connection. They are different epistemic descriptions of what happens to the individual following the intervention.

The causality lies in the physical intervention and in the subsequent dynamics of the organism. It does not lie between our descriptions of those dynamics.

Descriptions do not cause descriptions.

The problem with functions

This also raises a deeper problem for functionalism.

A function is not something we encounter in the brain in the same sense in which we encounter cells, molecules, electrical potentials, or chemical reactions.

We observe processes and describe some of their relations in terms of what they accomplish. We call something a memory function, a decision function, an integration function, or an information-processing function because we have selected a particular relation between processes and outcomes as relevant.

Functions are extraordinarily useful scientific abstractions.

But an abstraction should not be confused with the phenomenon from which it was abstracted.

This becomes crucial when functionalism argues that what matters for mentality is not the biological material but the functional organization. If the same functional relations can be realized in another substrate, the argument goes, the same mental states might also be realized there.

But this conclusion assumes precisely what has to be demonstrated: that the functional description is constitutive of the phenomenon rather than a description abstracted from it.

Functional equivalence establishes equivalence with respect to the specified function. It does not automatically establish phenomenal equivalence.

A computer may reproduce a functional relation we describe as memory, recognition, decision-making, or learning. That tells us that the specified relation can be technically reproduced. It does not yet tell us that we have reproduced what it means for a living individual to remember, recognize, decide, or experience.

The map may reproduce important relations in the landscape. It does not thereby become the landscape.

One individual, different descriptions

Perhaps the problem is therefore simpler than many theories of mind assume.

There is not a physiological organism on one side and cognition on the other, waiting for philosophy to explain how the two interact.

There is one living individual.

We can investigate this individual physiologically. We can measure neural activity, metabolism, electrical potentials, oscillations, connectivity, and countless other biological processes.

And we can investigate the same individual psychologically. We can ask questions, observe behavior, conduct experiments, collect reports, measure reaction times, and analyze statistical patterns.

These methods produce different kinds of descriptions because they provide different epistemic access to the same individual.

Neither description needs to be transformed into a second reality.

A person really can think, remember, suffer, perceive, and decide. Denying that these predicates name additional objects inside the brain does not make them unreal.

It simply puts them back where they belong.

The brain does not think. The individual thinks.

The brain is part of the biological organization that makes this possible. Understanding that organization is a scientific task of enormous importance.

But we should not mistake the vocabulary with which we describe the individual for additional machinery hidden inside the individual.

Otherwise we may spend decades trying to explain how one of our descriptions causes another.