The nature of the mind and the relation of the mind to the body and to the physical world have been vexing problems for modern philosophy. French mathematician, philosopher, and physiologist René Descartes formulated the most influential version of dualism, the view that the mind and the body are two different types of entities. As a physiologist, Descartes understood that the human body could be understood as a mechanism. He believed that the mind, being rational, could not be reduced to mechanistic physics. Therefore, he concluded that human beings consist of two distinct parts, a mind that is pure thought and a body that is extended in physical space. This raised questions of how pure thought could cause bodily action and how sensations in the flesh could be communicated to the spiritual half.

Many materialists have argued that the mind-body problem created by Descartes’s dualism is a result of a mistaken adherence to the concept of a nonphysical soul. Scientists have been able to identify areas of the brain responsible for speech, memory, and even personality traits. If the mind is seen as nothing but the electrochemical operations of the brain, though, this can create further problems. Thoughts, images, and emotions are not just influences on human behavior; they are also experiences in awareness, and it is difficult to find awareness in discharges of neurotransmitters.

In the preface to one of his later books, Consciousness Explained (1991), Daniel C. Dennett remarked that he had been hooked on the mind-body problem ever since his first year in college, when he read Descartes. Dennett’s first book, Content and Consciousness (1969), was an attempt to develop a unified, comprehensive theory of the mind as a product of mechanistic, physical forces. The seventeen essays in Brainstorms were efforts to revise and extend this theory by addressing different aspects of the nature of the mind.

A Theory of the Mind

In the introduction to Brainstorms, Dennett asserts that the essays collected in the book express a theory of the mind. He distinguishes his theory from two other physical theories. The first, and simplest, is what he calls “type identity theory.” This approach asserts that mental events are identical with physical events in the brain. Further, when two creatures have the same mental event, their brains must have something physical in common. Although Dennett accepts the identity of mental events and brain events, he denies that mental phenomena require common physical states. He points out that a clock and a sundial can both express the idea of “ten o’clock” while having no features in common except their purpose or function.

He calls the second theory of mind “Turing machine functionalism.” From this point of view, two computing, thinking, or feeling beings have the same mental event when they are in the same logical state, as when two different computers have the same program and are at the same place in this program. However, Dennett argues that two people may share the same idea, even though individuals vary in their backgrounds and physical-chemical brain structures, making it difficult to maintain that they have identical “programs.” Moreover, to say that mental events are logical states adds no real information to the description of mental states.

Dennett refers to his own theory as a version of “intentionalism.” Minds are intentional systems and mental events are intentional in character. An intentional system does consist of physical operations, but it cannot be reduced to these operations. Instead, it must be understood as possessing information and pursuing goals. From Dennett’s perspective, we do not understand beliefs or opinions by reducing them to neural activities but by examining carefully and critically the language that we ordinarily use to talk about beliefs or opinions in order to see how these are oriented toward goals.


The essays are divided into four parts. The three chapters of part 1 introduce the concept of an intentional system and examine arguments for Dennett’s version of intentionalism. An intentional system is one whose behavior can be understood and best predicted as a matter of beliefs, desires, and other such orientations. These systems can be entirely mechanical. A chess-playing computer, for example, is an intentional system because its activities can best be understood by thinking about it as following strategies to achieve goals.

Part 2 looks at the philosophical foundations of psychology. Dennett argues against the behaviorism of psychologist B. F. Skinner, who denied the scientific value of approaching psychology in terms of mental events. Skinner maintained that people and other animals should be understood in external, physical terms, as matters of behavioral responses to stimuli. Talking about behavior in terms of internal, mental occurrences such as desires, from Skinner’s perspective, involves a return to the mind-body dualism of Descartes. Further, if we say that action results from decisions or wishes, this is like saying they are consequences of an “inner man” making decisions or wishes. This would be no explanation at all because we would then have to explain how those desires or wishes were produced in the “inner man.” Dennett is sympathetic to Skinner’s physicalism, but maintains that Skinner fails to make the distinction...

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The Intentional Stance

Part 4 is the least technical section of the book, but it deals with some of the most profound implications of Dennett’s materialist perspective. Can human beings be seen as free moral agents from this perspective? The behaviorists answer that this is not possible because all human behavior is the result of operant conditioning. The Cartesian dualists would hold that the independence of the mind from physical and material influence is a precondition of freedom and moral responsibility. In the chapter “Mechanism and Responsibility,” Dennett lays out the different ways in which we can see the actions of organisms and other systems. We can, he says, take a “design stance,” in which we explain actions in terms of the way a system is designed. If we explain a computer’s activity by referring to its programming or human behavior by referring to the design of the nervous system, we are taking a design stance. We can also take a “physical stance,” in which the description of a system is based on knowledge of the system’s physical state. We generally take this stance when talking about why a machine will not work or when interpreting human behavior as a matter of physical or mental illness. Intentional systems, though, are just too complex to be explained in terms of design and the physical stance is usually only useful when the system is malfunctioning. Therefore, we take the “intentional stance,” in which we understand actions as choices among...

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Beyond Behaviorism

Because the essays in Brainstorms were meant to be delivered as talks, they are generally somewhat more approachable than Dennett’s first book. These essays therefore helped to bring the author’s ideas about intentionalism to a wider readership. The book received positive reviews in both specialized philosophical journals, such as the Philosophical Review, and in mainstream periodicals, such as Psychology Today and The New York Review of Books. The philosopher Douglas Hofstadter, in one review, praised Brainstorms as one of the most important pieces of thinking about thinking yet written.

Dennett’s chief achievement in this work was to demonstrate how one could take a materialistic approach to mental activity without reducing mental functions to the simple stimulus-and-response mechanisms of behaviorism. Many of the ideas in Brainstorms, such as the concept of the intentional system, the role of Darwinian evolution in shaping mental activity, and the “generate and test” model of thinking became key elements of Dennett’s later work.

The greatest impact of the book may have been its bringing engineering, artificial intelligence, and neurology into philosophical considerations of the mind-body problem and of the nature of human intelligence. Cognitive science, considered the domain of psychologists and computer scientists before Dennett began his work, became a central concern of philosophy because of the influence of Brainstorms and similar writings during the 1970’s. Dennett also helped to demonstrate the unity of cognitive science, showing how philosophers, engineers, and researchers in artificial intelligence could be seen as working on different aspects of the same problems.


(Student Guide to World Philosophy)

Additional Reading

Churchland, Patricia S. Neurophilosophy: Toward a Unified Science of the Mind/Brain. Cambridge, Mass.: MIT Press, 1986. An influential introduction to philosophy of mind based on research into brain structures, this is written by one of Daniel C. Dennett’s philosophical critics.

Dahlbom, Bo, ed. Dennett and His Critics: Demystifying Mind. Oxford: Blackwell, 1993. This is a collection of eleven essays that criticize and defend Dennett’s ideas. It includes an essay by Dennett himself, “Back from the Drawing Board.” The editor’s introduction is a good summary of the controversies surrounding the philosopher’s concepts. Some of the pieces strongly oppose Dennett’s theories. Readers should see especially “Fillin in: Why Dennett is Wrong,” by Patricia S. Churchland and V. S. Ramachandran.

Dawkins, Richard. The Extended Phenotype: The Long Reach of the Gene. Rev. ed. Oxford: Oxford University Press, 1999. A readable introduction to Darwinian biology by a thinker who influenced Dennett. Dennett wrote the afterword for this book.

Dennett, Daniel C. “A Conversation with Daniel C. Dennett.” Interview by Tom Flynn and Tim Madigan. Free Inquiry 15, no. 4 (Fall, 1995): 19-21. In this interview, Dennett discusses his view that consciousness is an illusion that arises from short-term memory. He also argues that ideas about ethics do not necessarily depend on religion or on the existence of an immortal soul.

Dennett, Daniel C. “Daniel C. Dennett.” Interview by Robert K. J. Killheffer. Omni 17, no. 8 (Fall, 1995): 119-120. An interview with Dennett about Consciousness Explained, artificial intelligence, Darwinian theory, and other topics. The interview takes place at Dennett’s farmhouse and it gives a good sense of the man behind the theories.

Dennett, Daniel C. Interview by editors of the Journal of Cognitive Neuroscience. Journal of Cognitive Neuroscience 7, no. 3 (Summer, 1995): 408-414. The interview focuses on Dennett’s views on the connections between cognitive science and philosophy.

Searle, John. Intentionality: An Essay in the Philosophy of Mind. Cambridge, England: Cambridge University Press, 1983. A view of the intentional nature of the mind that offers an alternative to Dennett’s view, written by one of Dennett’s chief philosophical opponents.

Shafto, Michael G., ed. How We Know. New York: Harper and Row, 1985. A collection of essays about the nature of thinking, including an essay by Dennett and several that are relevant to Dennett’s thinking.