Hobbes's Materialism: The Mechanical Philosophy of Human Nature
Thomas Hobbes's materialist philosophy: his rejection of immaterial substances, his mechanistic account of mind and morality, and his place in the history of materialism.
Hobbes was the most outspoken materialist of the seventeenth century and one of the founders of the modern materialist tradition. The materialism, like the political philosophy, was controversial in his own time and decisive for the subsequent development of the Enlightenment. The Leviathan and the De Corpore (1655) together present a complete account of the natural world, of human nature, and of the state and the citizen, all in terms of matter in motion. The materialism was the philosophical foundation of the political philosophy: if human beings are material bodies governed by the laws of motion, then the proper political life is one that is grounded in the analysis of those laws, rather than in the appeals to theology or to the classical tradition that the political philosophy of his predecessors had made.
The materialism also made Hobbes a target. He was accused of atheism by the Anglican establishment, and a parliamentary committee in 1666 ordered his books to be burned. The accusation of atheism was, in significant part, unfair. Hobbes accepted the existence of God, and he argued for the existence of God from the existence of motion (an argument that he developed in the De Corpore). But the God he accepted was the impersonal God of the deists — a being who had created the world and then withdrawn to let it run — and the angels, demons, and other spiritual beings that were part of the Christian tradition had no place in his philosophy.
The Mechanical Philosophy
Hobbes’s materialism is a version of the mechanical philosophy that had been developed by Galileo, by Descartes (in his natural philosophy, though not in his metaphysics), and by various other thinkers of the seventeenth century. The basic idea of the mechanical philosophy is that everything that happens in the natural world can be explained in terms of the motions of material bodies, and that the proper study of nature is the study of those motions.
Hobbes extended the mechanical philosophy to human nature. The human being, in Hobbes’s view, is a material body whose behavior is governed by the laws of motion, including the psychological laws that determine the passions and the will. The passions are motions of approach and avoidance — toward things that give us pleasure, away from things that give us pain. The will is the last appetite or aversion in a chain of deliberation. The mind is a complex of ideas that are the residues of past sensations. The “soul” is not an immaterial substance but a name for certain activities of the body.
The argument was, in Hobbes’s own day, deeply offensive to the religious and philosophical establishments. The establishment philosophers of the seventeenth century were committed to the Cartesian dualism of mind and body, and to the theological doctrines of the immortality of the soul and the freedom of the will. Hobbes denied all three. The denial of the immortality of the soul and of the freedom of the will was particularly offensive, and Hobbes was careful to publish the Leviathan in Paris rather than in England, where the licensing of books was more restrictive.
The Theory of Perception
Hobbes’s account of perception is a central part of his materialism, and it is one of the most powerful features of his philosophy. The account begins, in chapter 1 of the Leviathan, with the observation that the senses are the source of all the ideas of the mind. The senses, in Hobbes’s view, are motions in the brain that are caused by motions in the external world. The ideas that the mind has are the brain’s internal registrations of those motions. The “image” of an object is not, as the scholastic philosophers had thought, a kind of spiritual duplicate of the object; it is a set of motions in the brain, caused by the action of the object on the sense organs.
The argument is, in significant part, a version of the argument that Galileo had developed in The Assayer (1623). Galileo had argued that the “qualities” of objects — colors, sounds, tastes, smells — are not in the objects themselves, but in the response of the sense organs of the perceiver. The “primary” qualities of objects — size, shape, motion, number — are in the objects themselves; the “secondary” qualities are in the response of the perceiver. Hobbes adopted the distinction and applied it consistently to the human mind.
The implication of the argument is, in Hobbes’s view, that the mind is a kind of calculating machine. The “ratiocination” of the mind — the process of reasoning — is, in Hobbes’s view, a kind of computation with names. The logic of Hobbes’s Computation or Logic (1656) is the first systematic attempt to develop a formal logic in the modern tradition, and it is one of the most important works in the history of modern logic.
The Moral Philosophy
Hobbes’s moral philosophy is, like his philosophy of nature, a materialist account. The moral virtues, in Hobbes’s view, are not supernatural qualities implanted in the human soul by the divine creator; they are the qualities that are conducive to peace and self-preservation. The “law of nature” — the basic principle of Hobbes’s moral philosophy — is the conclusion of reason about the means to self-preservation. The first law of nature is that every person ought to seek peace, when he can have it, and to use all the advantages of war, when he cannot have it.
The argument was, in significant part, an attempt to provide a secular foundation for morality. The traditional moral philosophy had been based on the theory of natural law, which held that there are objective moral principles that are binding on all human beings, and that these principles can be known by reason. Hobbes accepted the theory of natural law in its broad outlines, but he rejected the traditional metaphysical and theological account of the foundations of natural law. For Hobbes, the laws of nature are the conclusions of reason about the means to self-preservation, and they are binding on human beings only because, and only insofar as, the institutional framework of the state makes them effective.
The argument was a source of the modern theory of moral relativism, and it was one of the main reasons why Hobbes was accused of atheism. The accusation was unfair in the sense that Hobbes accepted the existence of God and the basic structure of Christian morality. But the accusation was understandable in the sense that Hobbes’s account of the foundations of morality was incompatible with the traditional Christian account, which held that the moral law is a participation in the eternal law of God.
The Legacy
Hobbes’s materialism was one of the most influential and most controversial doctrines of the seventeenth century. The Leviathan was widely read, and the materialism became a basic feature of the modern philosophical tradition. Spinoza, who was deeply influenced by Hobbes, developed a more thoroughgoing materialist philosophy in his Ethics (posthumously published 1677). Diderot, in the eighteenth century, developed a materialist account of human nature in his philosophical dialogues, and the Encyclopédie that he edited was, in significant part, a vehicle for the materialist philosophy. The French materialists of the eighteenth century — Helvétius, d’Holbach, La Mettrie — were direct descendants of the Hobbesian tradition.
The British empiricist tradition of the eighteenth century — Locke, Berkeley, Hume — was, in significant part, a response to the Hobbesian challenge. Locke accepted much of Hobbes’s account of perception, but he rejected the more radical conclusions that Hobbes drew. Berkeley argued that the materialist account of perception is incoherent, and he developed an idealist alternative. Hume took the empiricist principles to their skeptical conclusion, and he developed a philosophy that was, in many ways, more radical than Hobbes’s own.
The contemporary relevance of Hobbes’s materialism is significant. The philosophy of mind, the philosophy of perception, and the philosophy of morality all continue to grapple with the questions that Hobbes first raised. The most important question is whether the mechanical philosophy of human nature can be reconciled with the contemporary understanding of the mind as a product of evolution, of culture, and of individual development. The contemporary defenders of Hobbes — most importantly the philosophers associated with the project of “moral psychology naturalized” — argue that the Hobbesian program can be updated to take account of the new sciences of the mind. The critics of Hobbes argue that the mechanical philosophy is fundamentally inadequate to the phenomena of consciousness, of moral responsibility, and of human freedom.
The debate is, in significant part, a debate about the legacy of the Enlightenment. The defenders of Hobbes argue that the Enlightenment is, at its core, a project of naturalizing the human world, and that Hobbes is one of the founders of the project. The critics of Hobbes argue that the Enlightenment is, at its core, a project of humanizing the natural world, and that Hobbes’s materialism is a betrayal of the project. The contemporary debate about the legacy of the Enlightenment is, in significant part, a debate about the legacy of Hobbes.