Rationalism vs Empiricism: Two Epistemological Traditions

The Enlightenment was the site of one of the great debates in the history of philosophy: the debate between the rationalists and the empiricists about the proper foundation of human knowledge. The rationalists held that certain fundamental truths could be known by reason alone, independent of experience. The empiricists held that all knowledge derived from experience, and that there were no innate ideas or rational intuitions that were independent of experience. This article compares the two traditions, examines their key differences, and considers the contemporary debate about their relationship.

The Rationalist Tradition

The rationalist tradition held that the proper foundation of human knowledge is reason, and that certain fundamental truths can be known by reason alone, independent of experience. The tradition was developed in the seventeenth century by the Continental philosophers, including René Descartes, Baruch Spinoza, and Gottfried Wilhelm Leibniz.

The basic principles of the rationalist tradition include:

The principle of innate ideas: the belief that the human mind is born with certain ideas or principles already in it, and that these ideas are the foundation of human knowledge.

The principle of the self-evidence of reason: the belief that certain truths are evident to reason, and that they do not require any empirical confirmation.

The principle of the deductive method: the belief that the proper method of inquiry is deduction, in which conclusions are derived from self-evident premises by rigorous logical reasoning.

The rationalist tradition was closely connected to the development of the new natural philosophy, especially the mathematical physics of Descartes and Newton. The rationalists believed that the proper method for the investigation of nature was the same as the proper method for the investigation of any other subject: the method of deductive reasoning from self-evident premises.

The Empiricist Tradition

The empiricist tradition held that the proper foundation of human knowledge is experience, and that all knowledge derives from experience. The tradition was developed in the late seventeenth and early eighteenth centuries by the British philosophers, including John Locke, George Berkeley, and David Hume.

The basic principles of the empiricist tradition include:

The principle of the tabula rasa: the belief that the human mind is, in its original state, empty of ideas, and that all knowledge derives from experience.

The principle of sensation and reflection: the belief that all ideas derive from two sources — sensation (the experience of the external world) and reflection (the experience of the operations of the mind itself).

The principle of the inductive method: the belief that the proper method of inquiry is induction, in which conclusions are derived from the careful observation of particular cases.

The empiricist tradition was closely connected to the development of the new experimental science. The empiricists believed that the proper method for the investigation of nature was the method of observation and experiment, in which conclusions are derived from the careful collection and analysis of empirical data.

The Key Differences

The two traditions differ in several important respects.

The first difference concerns the source of knowledge. The rationalists hold that the source of knowledge is reason, and that certain fundamental truths can be known by reason alone. The empiricists hold that the source of knowledge is experience, and that all knowledge derives from experience. The rationalists appeal to the self-evidence of reason; the empiricists appeal to the evidence of the senses.

The second difference concerns the proper method of inquiry. The rationalists advocate for the deductive method, in which conclusions are derived from self-evident premises by rigorous logical reasoning. The empiricists advocate for the inductive method, in which conclusions are derived from the careful observation of particular cases. The rationalist method is the method of mathematics; the empiricist method is the method of natural science.

The third difference concerns the proper scope of knowledge. The rationalists hold that the scope of knowledge is broad, and that reason can provide knowledge of the fundamental structure of reality, including God, the soul, and the nature of the universe. The empiricists hold that the scope of knowledge is more limited, and that reason alone cannot provide knowledge of the fundamental structure of reality. The proper scope of knowledge, for the empiricists, is restricted to the realm of experience.

The Key Thinkers

The rationalist tradition was developed by:

René Descartes (1596–1650), the founder of modern rationalism, whose Meditations (1641) developed the method of systematic doubt and the famous “cogito ergo sum” (I think, therefore I am).

Baruch Spinoza (1632–1677), whose Ethics (1677) presented a comprehensive rationalist account of God, nature, and human freedom.

Gottfried Wilhelm Leibniz (1646–1716), whose Monadology (1714) developed a rationalist account of the fundamental structure of reality.

The empiricist tradition was developed by:

John Locke (1632–1704), whose Essay Concerning Human Understanding (1689) developed the doctrine of the tabula rasa and the empiricist theory of knowledge.

George Berkeley (1685–1753), whose Treatise Concerning the Principles of Human Knowledge (1710) developed an idealist critique of Locke’s empiricism.

David Hume (1711–1776), whose Treatise of Human Nature (1739–1740) pushed the empiricist position to skeptical conclusions.

The Resolution

The debate between the rationalists and the empiricists was one of the central debates of the Enlightenment, and it was eventually transformed, but not resolved, by the work of Immanuel Kant. Kant’s Critique of Pure Reason (1781) attempted to mediate between the two traditions, arguing that knowledge is a product of both the senses and the categories of the understanding.

Kant’s resolution, in summary, was that the rationalists were right to insist on the active contribution of the mind to the constitution of knowledge, but wrong to insist that the mind could provide knowledge of the fundamental structure of reality independent of experience. The empiricists were right to insist on the importance of experience as the source of the materials of knowledge, but wrong to deny the active contribution of the mind to the organization of these materials.

The Kantian resolution has had a profound influence on the subsequent development of modern philosophy. The contemporary debate about the proper relationship between the rationalist and the empiricist traditions is, a continuation of the Kantian project.

Further Reading

• The Stanford Encyclopedia of Philosophy (plato.stanford.edu), relevant entry
• Mark Goldie & Robert Wokler, eds., The Cambridge History of Eighteenth-Century Political Thought (2006)
• Terence Ball, Reappraising Political Theory (1995)