Empiricism

In ancient times Aristotle was an empiricist relative to Plato's other-worldly rationalism. Modern empiricism began around 1600 with Francis Bacon (1561–1626), who promoted a new, experimental philosophy combining experience and reason, and with Galileo Galilei (1564–1642), who united experimental observation with a Platonic mathematical framework. Thomas Hobbes (1588–1679) further enriched early empiricist thinking, but the "big three" British empiricists were John Locke (1632–1704), George Berkeley (1685–1753), and David Hume (1711–1776). Locke first systematically expounded modern empiricism (see below). He was followed in the eighteenth century by Berkeley, notorious for his subjective idealism, the radical empiricist view that there are no material objects, that everything can be analyzed into minds and their ideas. Hume then took the further step of denying that there is even a substantial mind or ego. We introspect only a bundle of passing impressions. The mind is governed by natural laws of association, analogous to Isaac Newton's (1642–1727) law of gravitation, without needing an executive overseer. Hume also denied that inductive inference can be justified by logical argument, but he defended a wider conception of rationality (or at least sensible action) based on our natural impulses to believe and act. As he wrote in A Treatise of Human Nature (1739–1740) and its popularization, An Enquiry Concerning Human Understanding (1748), passion or custom, not reason, is "the great guide of human life."

The leading nineteenth-century empiricist was John Stuart Mill (1806–1873), who developed a full-fledged phenomenalism. Mill held that simple induction by enumeration (ravens 1, 2, 3, … n are black; therefore all ravens are black) is sufficient to support both science and mathematics: even the principles of logic and mathematics are very general empirical laws. Twentieth-century empiricists such as Bertrand Russell (1872–1970), George Edward Moore (1873–1958), and Alfred Jules Ayer (1910–1989) denied this, as did the logical empiricists of the Vienna Circle, who contended that the laws of logic and mathematics are both a priori and analytically true, that is, true by virtue of logical form and our linguistic conventions, hence completely empty of empirical content. By contrast, many twentieth-century thinkers, following Willard Van Orman Quine (1908–2000), have returned to a more naturalistic pragmatism.

The most damaging criticisms of British empiricism were leveled first by Immanuel Kant (1724–1804) and by the German and British idealists who followed him, then by Ludwig Wittgenstein (1899–1969), Gilbert Ryle (1900–1976), Quine, Wilfrid Sellars (1912–1989), Thomas Kuhn (1922–1996), and other twentieth-century figures, who attacked the entire Cartesian-Lockean conception of mind, experience, and language. Shocked by Hume's apparent skepticism about causality and Newtonian science, Kant synthesized rationalism and empiricism, while critically transcending both. The human mind itself furnishes the conceptual and rational apparatus necessary to organize our experience, as he argued in his Critique of Pure Reason (1781). "Concepts without percepts are empty; percepts without concepts are blind." Kant retained a vestige of the rationalist idea that we possess a special sort of intuition that enables us to make substantive, "synthetic" claims about the world that are nonetheless known a priori. He held that Euclidean geometry and the basic principles of Newtonian mechanics are such "synthetic a priori" truths. Post-Kantian empiricists deny this.