Spinoza; drawing by David Levine

In his recently published memoir The Making of a Philosopher,* Colin McGinn makes a provocative suggestion. It may be found, he writes, that human beings will never be able adequately to explain to themselves the relation of their minds to their bodies and brains; that relation may remain a philosophical mystery forever. For him, reality at this point, in Kant’s famous phrase, is “not adapted to our powers of cognition.” McGinn tells us that Noam Chomsky inspired this despair. This reminded me of a conversation I had with Chomsky many years ago, on American radio, in which we discussed whether physicists, rather than trying to go further in physical science itself, might finally choose to investigate the intellectual and physical limits on our capacity to add to our physics.

But any such pessimistic thesis about the limits of theory is a challenge to philosophy itself and also to the history of philosophy. Do we really think that contemporary analytical philosophers, standing tall on the shoulders of their predecessors, are in a position to predict the future of thought? Surely analytical philosophy as it now flourishes in Britain, the US, Australia, and a little elsewhere, is a transient episode in a complicated and endless story of philosophy, with many ups and downs in the past, and many more to be expected. We are not moving toward a final enlightenment and there is no assured teleology. There is a recurring pattern of sporadic discoveries or inventions by a truly original thinker, followed by some reaction against the discovery.

Compare the history of philosophy with the history of painting. A great painter appears, Giotto or Caravaggio or Cézanne, and nothing is ever the same again; his followers exploit the new opportunities opened up for them, and consequently we enter a new room in the museum. So also in the progress of philosophy, which draws upon the rare thinker of genius. Human beings are perpetually puzzled about, and made uneasy by, their dubious status in the natural order, and the history of religions and of philosophy are their best efforts to do something about it. It would be a deadly, but not uncommon, provincialism to take the brightest epigones of our own period as the most advanced, and therefore as the most enlightened, philosophers of all time.

One might plausibly think that the best philosophers, the most coherent and the most powerful with arguments, are now all dead, and that we must wait for an uncertain future to encounter their equals, or possibly even their superior. The future prospects of philosophy, and therefore the evaluation of contemporary developments, are shrouded in total uncertainty. We cannot know which of the now most prized insights of the last fifty years will survive for another fifty years into a changed environment of science and of social needs.

When writing about Spinoza in 1950 in the heyday of a kind of logical positivism, I came to think that he had probably come nearer than any empiricist philosopher to unraveling the two great mysteries, the mind–body relationship and the nature of mathematical knowledge. Perhaps I was right, but an advance will come only from the unfurling of new arguments and even new kinds of argument. Great mental energy is needed to break through the accepted agenda of any particular period in philosophy. In 1918 Bertrand Russell knew that he had already lost that energy. In American universities now philosophy seems to a visitor to be a greatly respected discipline and sometimes even a fashionable one. Since fashion drives most inquiries and activities above the level of urgent needs, one ought to look forward to yet one more breakthrough in thought.

The most hotly debated topic of the moment in Anglo-American philosophy is McGinn’s “unanswerable question”: How are we to account for consciousness, and the subjective aspect of experience, and their place in the natural order? Although Spinoza is not often cited in current discussions I think that he suggested an obscure beginning of an answer, which it is difficult to summarize and to compress. Think of four other oppositions that we find both pervasive and puzzling: (1) between a person or thing as active versus passive in its interaction with other things; (2) between that person or thing being free versus externally determined in its behavior; (3) between that person’s or thing’s behavior being explained by reference to its goals, teleologically, or by reference to laws of motion, deterministically or probabilistically; (4) lastly, I think of the opposition between individuals (persons and things), each of whom has a distinct character, and on the other hand ultimate particles (e.g., electrons and photons), which do not have distinct individual characters and are conceived by physicists to be all the same. If we put these four dichotomies together, we shall realize that, taken together, they can compose a single opposition, which we apply in our thinking about the natural order, not only to human beings, but to all things in the common order of Nature. The first of the pair can be called Thought, Descartes’s name, and the second, Extension, a concept recalling Descartes’s idea of the mind as a thinking thing that is not extended and the body as a thing that is extended and does not think.


Why is this single opposition inadequate? Human beings have acquired through natural processes an extra faculty and power incorporated in the brain: the power of reflexive knowledge. They can be aware of their own desires, beliefs, and purposes. Consciousness, in the sense of the thing that one loses when one falls asleep or is anesthetized, is knowledge of one’s own purposes.

The next step we need to take is to abandon what has been called the bucket theory of the mind, as in Descartes and most empiricist philosophers, according to which, in perception, ideas arrive through the senses into a receptacle, where they are processed. This is the wrong picture. There is no perception without activity and thought, and all perception is an interaction with an external reality. When you see a sapphire, the blueness you experience is the active and subjective aspect of the transaction, which has also its physical and objective aspect. And so throughout all our perceptions and passions.

I am suggesting the substitution of an old metaphysical framework, darkly indicated in Spinoza’s Ethics, for other metaphysical frameworks that have proved unhelpful. For Spinoza all activities in nature have two aspects; they have an inner design, and this design is embodied in evident movements or changes.

It is evidently a mistake to follow Descartes in thinking of soul and body as two distinct domains of being created by a transcendent God. For Spinoza, God is identical with the natural order, which creates itself. We do better, Spinoza’s work suggests, to think of human beings, composed of soul and body, as medium-sized objects in the common order of Nature who observe physical things, including parts of their own bodies, and who at the same time are aware of themselves as the subjects initiating movement and observing the environment. They know that they must move (their eyes, their head, their standpoint) if they are to achieve objectivity in their observations, without which they cannot survive. Their knowledge of their own movements is not primarily to be found in observation, but in their sense of their own purposes and intentions, which are thoughts, and which follow laws of thought. This subjective knowledge is continuously available to the person, whenever he is conscious. We live our lives within this schema of inner and outer experience, of soul and body intertwined, and we cannot, without inconsistency, think of any other model of individual existence. The whole natural order, not only ourselves, exhibits purposes, activities, and laws of motion thus intertwined.

But a critic will ask, “How is it that our normal intuitions are so far from the truth, as you reconstruct it? How is it that our everyday language incorporates Descartes’s dualistic scheme in which reality is divided into two self-contained domains, Thought and Extension, which cannot intelligibly interact and which therefore generate ‘unanswerable questions’?” The Spi-nozistic answer is clear: because our ancestors have always needed, for emotional reasons, to believe that the natural order was created by a transcendent God distinct from his creation and that he must have designed the two self-contained divisions of reality, Thought and Extension. As soon as we have grasped that the idea of a transcendent creator is incoherent, and that God and Nature, the immanent cause and the order caused, must be identical, we shall infer that the natural order must be essentially undivided, and that its fundamental features, as we perceive them, must have emerged within it. We have evolved as mind-bodies without supernatural privileges but with a natural capacity for reflection installed in our brains. When we reflect rigorously, we shall see that our ordinary language conveys “the metaphysics of the Stone Age,” as Russell used to say. The Stone Age is only slowly slipping away.

I can imagine Spinoza saying with a grave smile:

You despair. I told you so. As long as you persist in envisioning souls and bodies as elements in a natural order, created by a creator outside his creation, who has designed two domains of reality, Thought and Extension, distinct but somehow interacting, you will find yourself in a hopeless muddle and confusion when you come to reflect on how this picture fits together. You must first accustom yourselves to think of yourselves as mind-bodies intertwined, and to think of Thought and Extension as two universal and permanent features of the activities of all living things in the common order of Nature as we perceive it. An order of causes conceived of as a sequence of thoughts and subjective experiences is always identical with a sequence of objective changes in brain and body; and the reverse is also true. The duality of subjective and objective aspects of perceptions and activities runs throughout Nature as we perceive it.

But the skeptic will ask: “How are you entitled to misuse the concept of identity in such a way that a process of subjective experiences and of thought is identical with a sequence of physical states?” The authority for this use comes from what Spinoza called the conatus, the drive for self-maintenance against disruptive forces coming from inside or outside the organism. All individuals are held together in their activities by this drive. When as patriots we salute the flag, then as persons we know that the soul or purpose of the action is involved or entwined with the motion of the arm. Only when a person turns to causal explanation and control does the duality become salient and effective. He knows that he can stop the saluting behavior either by paralyzing the arm or by canceling the purpose with new thoughts. Subjective experiences and thoughts are part of the private history of individuals, while changes in brain and body are observable by all the world and are subject to laws of motion presumed to be universal.


Because he was primarily interested in morality, in politics, and in the prudent conduct of life, Spinoza had the extraordinary originality to question how a convinced materialist would live his own life from day to day, coping with his own desires and his own passions. Hobbes, like most materialists, stated his materialism from the standpoint of an observer rather than that of an acting person, and he left no place for reflective knowledge or for any equivalent power of mind. He could not therefore give a coherent account of persons as self-correcting agents, as Spinoza does.

Both in Spinoza’s Ethics and in his De Intellectus Emendatione activity is the central concept. Even the enjoyment of the sapphire’s blue counts for Spinoza as an activity of mind. And the individual is of course no kind of substance, but rather a changing collection of the myriad activities of a person in his role as agent and as a source of initiatives.

When one appreciates the force and self-assertion of all living things, one will no longer want to play with ghosts in philosophy—including souls as quasi substances. Spinoza claimed that he knew that his philosophy was true. I am sure that this superb claim was wrong. Metaphysics, as is Spinoza’s Ethics, is speculation, which at best is plausible and coherent, but certainly is not knowledge.

This Issue

October 24, 2002