John Locke

John Locke (1632–1704) was an English physician and philosopher regarded as the principal architect of classical liberalism and the empiricist tradition in epistemology. His two foundational works are the Two Treatises of Government (1689) and An Essay Concerning Human Understanding (1690), supplemented by the Letter Concerning Toleration (1689). Writing in the aftermath of the English Civil War and immediately after the Glorious Revolution of 1688, Locke produced a systematic justification for constitutional, consent-based government that displaced the divine-right absolutism defended by Sir Robert Filmer in Patriarcha, against which the First Treatise is directed.

Locke's political theory begins from a "state of nature" governed by a law of nature accessible to reason, in which all individuals possess inalienable natural rights to life, liberty and property. Unlike Thomas Hobbes, whose state of nature was a "war of all against all," Locke's was a condition of imperfect peace whose chief defect was the absence of an impartial judge to resolve disputes. To remedy this, individuals consent to form civil society and government, surrendering only the right of private enforcement. Sovereignty thus rests on the consent of the governed, government is held in trust, and the people retain a right of revolution when rulers violate that trust — a doctrine that legitimised resistance to tyranny. His labour theory of property held that an individual acquires property by mixing labour with nature's commons. In epistemology, Locke rejected innate ideas, describing the mind at birth as a tabula rasa (blank slate) furnished entirely by sensation and reflection — the cornerstone of British empiricism later developed by Berkeley and Hume.

Locke's ideas decisively shaped the modern democratic world. Thomas Jefferson borrowed Locke's triad almost verbatim in the United States Declaration of Independence (1776), substituting "pursuit of happiness" for property; his separation of powers and limited-government principles influenced Montesquieu and the framers of the U.S. Constitution. His Letter Concerning Toleration advanced the separation of church and state and freedom of conscience. In ethics and political theory, Locke remains the canonical exponent of deontological natural-rights liberalism contrasted with utilitarian and communitarian alternatives. His thought continues to anchor contemporary debates on individual liberty, property rights, and the legitimacy of state authority in liberal-democratic constitutionalism.

For UPSC aspirants, Locke is doubly relevant. In GS Paper IV (Ethics) he features under "contributions of moral thinkers and philosophers," where questions probe his natural-rights deontology, the social-contract account of political obligation, and comparison with Hobbes and Rousseau — the three classic contract theorists. Candidates should be able to apply his consent and trust framework to case-study questions on legitimate authority and citizens' resistance to unjust laws. In World History he is tested as an intellectual catalyst of the Enlightenment, the American and French Revolutions, and the broader transition from absolute monarchy to constitutional government. The standard exam angle asks candidates to distinguish the three social-contract theorists on the state of nature, the nature of the contract, and the locus of sovereignty.