Minds, Brains and Science

1. The Mind-Body Problem: Mental Phenomena as Brain Features

Pains and other mental phenomena just are features of the brain (and perhaps the rest of the central nervous system).

Brains cause minds. Mental phenomena, whether conscious or unconscious, are caused by processes occurring in the brain. This perspective challenges traditional dualism by asserting that mental states are not separate entities but rather emergent properties of brain activity. For example, the sensation of pain arises from a series of events starting at nerve endings and culminating in the thalamus and sensory cortex.

Micro/macro distinction. The relationship between mind and brain mirrors the micro/macro distinctions found in physics. Just as the liquidity of water is caused by the behavior of H2O molecules yet is a feature of the water itself, mental states are caused by neuronal activity and are simultaneously features of the brain. This avoids the pitfall of viewing the mind as an immaterial substance interacting with the physical brain.

Addressing the challenges. This approach directly addresses the challenges posed by consciousness, intentionality, subjectivity, and mental causation. Consciousness is a biological phenomenon caused by specific electrochemical activities in the brain. Intentionality arises from brain processes that are about something. Subjectivity is an objective fact of biology, and mental causation occurs because mental states are features of the brain with causal powers.

2. The Syntax vs. Semantics Divide in AI

There is more to having a mind than having formal or syntactical processes.

Computers lack semantics. Digital computers, by definition, operate on formal or syntactical structures, manipulating symbols without inherent meaning. Minds, however, possess semantics – the capacity to understand and attach meaning to these symbols. This fundamental difference renders the "strong AI" claim that computers can truly think untenable.

The Chinese Room Argument. Searle's thought experiment illustrates this point vividly. A person locked in a room, following rules to manipulate Chinese symbols, can produce outputs indistinguishable from a native Chinese speaker, yet without understanding Chinese. This demonstrates that implementing a program, regardless of its complexity, is insufficient for genuine understanding.

Implications for AI. The argument underscores that mere simulation of mental processes does not equate to duplication. While computers can simulate various processes, including mental ones, these simulations do not possess the intrinsic qualities of consciousness, intentionality, and subjectivity that characterize genuine minds. The focus should shift from creating programs that mimic intelligence to understanding the biological processes that give rise to it.

3. Cognitive Science: Beyond Computer Metaphors

The computer is probably no better and no worse as a metaphor for the brain than earlier mechanical metaphors.

Thinking is not just symbol manipulation. Cognitivism posits that thinking is information processing, which is symbol manipulation, and thus best studied through computational programs. However, this view overlooks the crucial role of meaning and content in human thought. Human rule-following is guided by the semantic content of the rules, whereas computers merely act in accordance with formal procedures.

The "as if" fallacy. Describing brain processes as "information processing" can be misleading if it conflates psychologically real processes with mere "as if" descriptions. Just as water running downhill can be described as processing information about the terrain, this doesn't imply any psychological relevance. The brain's real psychological processes and neurophysiology are what matter.

Alternative approach. Instead of seeking a computational program between the mind and brain, we should view mental processes as biological phenomena. This involves studying the neurophysiological levels of description and the mental levels of description, without assuming an intermediate level of digital computational processes. This approach acknowledges the complexity and biological basis of the mind.

4. The Structure of Action: Intentionality and Causation

The explanation of an action must have the same content as was in the person's head when he performed the action or when he reasoned toward his intention to perform the action.

Actions have mental and physical components. Human actions consist of both a mental component (an intention) and a physical component (bodily movement). The intention determines the success or failure of the action and, if successful, causes the bodily movement. This intentional causation is central to understanding the structure and explanation of action.

Intentional causation. This form of causation differs from standard textbook accounts. It involves the mind bringing about the very state of affairs it has been thinking about. For example, the intention to raise one's arm causes the arm to rise. This is distinct from billiard ball causation, where one physical object impacts another.

The network and background of intentionality. Intentional states function within a network of other intentional states, such as beliefs and desires. Furthermore, this network operates against a background of capacities, abilities, skills, and habits that are not themselves intentional states. This highlights the complexity and context-dependence of human action.

5. Social Sciences: The Intrinsically Mental Character

The radical discontinuity between the social and psychological disciplines on the one hand and the natural sciences on the other derives from the role of the mind in these disciplines.

Social phenomena are mind-dependent. Social phenomena, such as marriage, money, and property, are defined in terms of the psychological attitudes people hold towards them. This means that the concepts themselves are constituents of the phenomena. For example, something counts as money because people use it as and think of it as money.

No physical limits. The defining principles of social phenomena place no physical limits on their realization. This lack of systematic connection between the physical and social properties prevents the formulation of strict laws in the social sciences. Unlike the gas laws, which are grounded in the behavior of particles, social laws lack this grounding.

The true character of social sciences. The social sciences are about various aspects of intentionality. Economics, for example, assumes that entrepreneurs seek profit and consumers prefer to be better off. Linguistics studies the rules that relate sounds and meanings in natural languages. These disciplines are grounded in human practices and intentionality, making them context-dependent and historical.

6. The Illusion of Free Will: Determinism vs. Experience

If there is any fact of experience that we are all familiar with, it's the simple fact that our own choices, decisions, reasonings, and cogitations seem to make a difference to our actual behaviour.

Determinism's challenge. Determinism posits that all events, including human actions, are causally determined by prior events. This view leaves no room for genuine freedom of the will, as everything is predetermined. Even indeterminacy at the level of particle physics does not support free will.

The experience of freedom. Despite the deterministic view, we have a strong conviction of our own free will based on our experiences of making choices and decisions. We feel that we could have done otherwise and that our choices make a difference. This sense of freedom is a fundamental aspect of our self-conception.

Compatibilism's inadequacy. Compatibilism attempts to reconcile free will and determinism by arguing that free actions are those not constrained by external forces or psychological compulsions. However, this view fails to address the core question of whether we could have done otherwise, all other conditions remaining the same. It denies the substance of free will while maintaining its verbal shell.

7. Reconciling Science and Freedom: A Persistent Conundrum

We find it easy to give up the conviction that the earth is flat as soon as we understand the evidence for the heliocentric theory of the solar system.

Bottom-up causation. The scientific view of the world operates from the bottom up, explaining surface features in terms of microparticles. Mental features are caused by and realized in neurophysiological phenomena. This bottom-up causation leaves little scope for free will, as the mind can only affect nature insofar as it is part of nature, and its features are determined at the micro-levels of physics.

The experience of acting. Our conviction of freedom is tied to consciousness and, specifically, the experience of engaging in voluntary, intentional human actions. This experience carries the sense that "I am making this happen" and that "I could be doing something else." This sense of alternative courses of action is built into the experience of acting.

A persistent conundrum. We cannot give up our conviction of freedom because it is built into every normal, conscious intentional action. We act on the assumption of freedom, regardless of our understanding of the world as a determined physical system. This creates a persistent conundrum between our scientific understanding and our lived experience.

Last updated: February 26, 2025