Cover page

Table of Contents

blackwell great minds

title page

copyright page




chapter 1: locke's life

chapter 2: the nature and role of ideas

chapter 3: the negative project: against innatism

chapter 4: the positive project: ideational empiricism

4.1 Simple Ideas

4.2 Sensation and Reflection

4.3 Complex Ideas

4.4 Abstract Ideas

4.5 Challenges to Ideational Empiricism: The Ideas of Infinity and Substratum

chapter 5: substances

5.1 Body, Matter, Space, and Vacuum

5.2 Spirit

chapter 6: qualities

chapter 7: mental operations

7.1 Actions and Passions

7.2 Will and Willing

7.3 Voluntariness and Involuntariness

7.4 Freedom, Necessity, and Determination of the Will

7.5 A Problem

chapter 8: relations

8.1 Identity and Diversity

8.2 Moral Relations

chapter 9: language

9.1 Language and Meaning

9.2 The Imperfections and Abuses of Language

9.3 Nominal Essence, Real Essence, and Classification

chapter 10: knowledge and belief

10.1 The Official Account of Knowledge

10.2 The Degrees of Knowledge

10.3 Anti-Dogmatism and Anti-Skepticism

10.4 Faith and Religious Enthusiasm

chapter 11: moral philosophy

11.1 Morality and God's Will

11.2 Natural Law

11.3 Punishment and Slavery

11.4 Property

11.5 Family

chapter 12: political philosophy

12.1 Political Society

12.2 Legitimate Rule

12.3 Varieties of Illegitimate Rule

12.4 Toleration


blackwell great minds

edited by Steven Nadler

The Blackwell Great Minds series gives readers a strong sense of the fundamental views of the great western thinkers and captures the relevance of these figures to the way we think and live today.

1 Kant by Allen W. Wood
2 Augustine by Gareth B. Matthews
3 Descartes by André Gombay
4 Sartre by Katherine J. Morris
5 Charles Darwin by Michael Ruse
6 Schopenhauer by Robert Wicks
7 Shakespeare's Ideas by David Bevington
8 Camus by David Sherman
9 Kierkegaard by M. Jamie Ferreira
10 Mill by Wendy Donner and Richard Fumerton
11 Socrates by George H. Rudebusch
12 Maimonides by T.M. Rudavsky
13 Wittgenstein by Hans Sluga
14 Locke by Samuel C. Rickless
Title page

To my mother,

Regina Sarfaty Rickless


Writing a book on the most important themes of John Locke's entire philosophical output is a singular challenge. One of the reasons he was such a great philosopher is that he was remarkably knowledgeable and instinctively curious, with a penchant for clarity and systematicity. His work covers topics in the philosophy of mind, metaphysics, philosophy of language, epistemology, moral philosophy, and political philosophy. I have done my very best to provide a concise, clear, and, I hope, relatively accessible conspectus of Locke's contributions in these areas. I would have liked to have been able to discuss more of Locke's theological views, as well as the details of his investigations into natural philosophy (science). But I had to leave these matters to one side for reasons of space. Readers who are interested in these topics will learn a great deal from the work of Victor Nuovo (on the first) and Peter Anstey (on the second), among others.

I have many people to thank for helping me to bring this book to fruition. First and foremost, I am grateful to Steven Nadler and the editorial staff at Wiley Blackwell for granting me the commission, and I thank Gideon Yaffe for encouraging me to take it. Although I had spent some years thinking about various aspects of Locke's philosophy, I had certainly not thought through his views on all the matters covered in the pages to follow. As I wrote, I tried out chapters (or parts thereof) on two audiences, for whose patience and constructive comments I am very grateful: the Roger Woolhouse Memorial Conference at the University of York in June–July 2012, and the History of Philosophy Roundtable at UCSD – with special thanks to Donald Baxter, Martha Bolton, Justin Broackes, Lisa Downing, Paul Lodge, Antonia LoLordo, Peter Millican, Lex Newman, Pauline Phemister, Gonzalo Rodriguez-Pereyra, Timothy Stanton, and Tom Stoneham. For their supremely clear-eyed and helpful contributions on a variety of matters Lockean, whether in conversation or on paper or both, I would also like to thank Peter Anstey, Margaret Atherton, Vere Chappell, Michael Jacovides, Nick Jolley, Jessica Gordon-Roth, Ruth Mattern, Ed McCann, David Owen, John Simmons, Galen Strawson, Matthew Stuart, Udo Thiel, Bill Uzgalis, Jeremy Waldron, Ken Winkler, Roger Woolhouse, and Gideon Yaffe: it really does take a village. For supporting my research with the help of a grant that enabled me to purchase most of Locke's correspondence, I would like to thank the UCSD Dean of Arts and Humanities, Seth Lerer, from whom I also learned a great deal about Locke's philosophy of education and his appreciation for, and translation of, Aesop's fables.

For their moral support and willingness to help me parcel out my research and teaching time in the most efficient way possible, I am very grateful to my colleagues David Brink and Don Rutherford, both of whom sacrificed a great deal as (consecutive) department chairs in order to make the UCSD philosophy department the vibrant and stimulating intellectual community that it is. The community of historians of philosophy at UCSD, including my colleagues David and Don, Eric Watkins, Clinton Tolley, Michael Hardimon, and Monte Johnson, and my doctoral student, Nate Rockwood, made excellent suggestions and provided useful objections that contributed to improvements in the book. More than anything, I thank my lucky stars for the fact that my wife and colleague, Dana Kay Nelkin, and our two wonderful children, Sophie and Alice, make it possible for me to live and work in an environment pervaded by intellectual honesty, boundless curiosity, and untrammeled love.

My first ever publication (in 1997) was on Locke's distinction between primary and secondary qualities. When I received the offprints, I immediately sent one to my mother. When I next visited her, she had found a special stand for it and had given it a prominent place in her study. Every day of my life she has been proud of me and given me unconditional love and support. So this book is dedicated to you, Mom: wife, mother, and opera singer extraordinaire. Thanks for everything, but especially for the banana cream pie.


AT Oeuvres de Descartes, revised edition, edited by Charles Adam and Paul Tannery. Paris: Vrin/CNRS, 1964–1976.
CSM 1, CSM 2 The Philosophical Writings of Descartes, vols. 1 and 2, translated by John Cottingham, Robert Stoothoff, and Dugald Murdoch. Cambridge: Cambridge University Press, 1985, 1984.
CSM 3 The Philosophical Writings of Descartes, vol. 3, translated by John Cottingham, Robert Stoothoff, Dugald Murdoch, and Anthony Kenny. Cambridge: Cambridge University Press, 1991.
Draft A, Draft B   Drafts for the Essay Concerning Human Understanding and OtherPhilosophical Writings, edited by Peter H. Nidditch and G.A.J. Rogers. Oxford: Clarendon Press, 1990.
E An Essay Concerning Human Understanding, edited by Peter H. Nidditch. Oxford: Clarendon Press, 1975.
ELN Essays on the Law of Nature and Associated Writings, edited by W. von Leyden. Oxford: Clarendon Press, 1954.
T1, T2 Two Treatises of Government, edited by Peter Laslett. Cambridge: Cambridge University Press, 1960. Cited by section number only.
W The Works of John Locke. A New Edition, corrected, 10 vols. London: printed for Thomas Tegg, 1823.

chapter 1

locke's life

If you ask what sort of a man he was, the answer is that he was contented with his modest lot. Bred a scholar, he used his studies to devote himself to truth alone.

Locke's description of himself, translated by Roger Woolhouse from the original Latin on his tombstone

John Locke was an accidental philosopher. For most of his intellectual life, he was attracted to the kinds of activities engaged in by the research scientists of his day: collecting data, formulating explanatory hypotheses on the basis of observation, and testing hypotheses by controlled experiments. But because of a broad and insatiable intellectual curiosity and a devotion to truth wherever it lay, as well as a deep antipathy to absolute power and its abuses, Locke found himself drawn into a number of important philosophical and political controversies that, as he saw it, required clear definition of terms, precise reasoning, and a firm grasp of the extent and limits of human understanding. His impatience with what he saw as the fruitless and endless disputation of his more Scholastically minded contemporaries, combined with his own investigations into the mental abilities of human beings and his liberal views on the inclusive nature of Christianity and the importance of toleration, led him to defend a number of controversial philosophical and theological doctrines that more than ruffled the feathers of prominent Anglican (Church of England) clergymen. His claim that the legitimacy of government is grounded in the consent of the people was anathema to supporters of the divine right of kings and of the importance of absolute rule as a bulwark against chaos and civil war. He was mostly lucky in that he was able to devote much of his life to the pursuits that gave him the greatest satisfaction: observing, cataloguing, discovering, reading, writing, and sharing ideas with like-minded friends. And he lived long enough and worked sufficiently tirelessly to leave us with a priceless intellectual legacy, one that rivals, in both quality and influence, the output of the rest of the Western world's greatest philosophers.

John Locke was born in Wrington, Somerset, in 1632, and spent the first 14 years of his life in the village of Belluton, 6 miles south of the thriving market town of Bristol. His mother, Agnes Keene, and father, John, 10 years her junior, lived in a house given to them by Locke's grandfather, who had made his fortune in the cloth trade. In later years, Locke would describe his mother as very pious and affectionate, but little else is known about her. He also had kind things to say about his father, approving of the strict discipline with which he was raised before adolescence and the gradual loosening of this discipline thereafter, allowing for the possibility of true friendship between parent and son in adulthood. Of Locke's two brothers, one died in infancy, and the other, Thomas, five years younger than John, died in 1663, most likely of tuberculosis.

Locke's parents were probably Puritans, Calvinists who leaned towards Presbyterianism. As Protestant dissenters, they opposed Anglican orthodoxy and demands for uniformity, as well as Catholicism. No doubt this dual hostility had a significant impact on Locke, much of whose later theological output (perhaps unsurprisingly) reflected the basic attitudes of his parents. Locke's father was a lawyer, charged in part with collecting local taxes to support the increasingly unpopular administration of King Charles I, who believed in his divine right to absolute rule. In 1642, when Locke was 10 years old, a two-year standoff between Parliament and Charles I led to civil war. Locke's father, at some cost to himself, joined a Parliamentary regiment organized by a local MP, Alexander Popham. The regiment was defeated, and John Sr returned home in 1643. But thanks to Popham's power to nominate boys for entrance into selective private schools, Locke's father was able to secure a place for him at Westminster School in 1646.

At Westminster, Locke's curriculum consisted of a steady diet of Latin, Greek, Hebrew, and Arabic, with some geography, arithmetic, and geometry (taught in Latin). Locke later described the school atmosphere as very severe, awash with the kind of corporal punishment he never ceased to detest. In 1649, Charles I was beheaded, and his son, Charles II, was defeated by Oliver Cromwell in 1651 and fled to the continent. In 1650, Locke earned a special scholarship that enabled him to board at Westminster and compete, successfully in 1652, for a place at Christchurch College, Oxford.

Locke's program of study at Christchurch was an extension of the Westminster curriculum, with the addition of lectures and tutorials on Aristotelian Scholastic logic, metaphysics, and moral philosophy, and a method of learning grounded in disputation, akin to what we now think of as formal debate. Locke developed a lifelong antipathy to Aristotelian doctrines (particularly to the procrustean conventions of syllogistic logic and the obscure terms and useless questions of Scholastic metaphysics) and to the method of disputation, which he thought inconducive to knowledge or discovery.

Locke's mother died in 1654, when he was 22, and the next year he was graduated with a BA from Oxford. He thought briefly of studying law, but returned to Christchurch to seek an MA, which included a slightly more extensive program of Scholastic study, including “natural philosophy” (i.e., science). By the time he earned his MA in 1658, Locke had a reputation as a very learned and ingenious scholar. In 1659, perhaps thinking of finding a spouse, Locke began spending time (and exchanging letters) with Elinor Parry, then 18, whose brother was a student at Jesus College. Neither Locke nor Elinor was willing to commit to anything more than friendship, and the correspondence shows evidence of ups and downs in the relationship, though over the next few years Elinor's interest in the possibility of more serious attachment grew.

After Cromwell's death in 1658, there was a brief battle for succession. Cromwell's son, Richard, was defeated in 1659 and Charles II was restored to the throne. Though unclear beforehand which way to lean, Locke embraced the Restoration as a form of “quiet and settlement.”1 Despite Charles II's liberal attitude to dissenters, a Parliamentary bill for religious (Anglican) uniformity was passed in 1661, the year of Locke's father's death. Worried about the consequences of a crackdown on dissenters, Locke wrote two (unpublished) Tracts on Government (in 1660 and 1662) supporting toleration of freedom of conscience, but trusting the king to enforce uniformity of religious practices as a way of preventing religious war. At the time, Locke was enjoying life as a student, making friends with the experimental chemist Robert Boyle (1627–1691), relishing his study of medicine, and gaining appreciation for the intelligibility (even if not the truth) of the physics of René Descartes (1596–1650).

Between 1661 and 1667 Locke was elected to various posts at Oxford: Lecturer in Greek, Lecturer in Rhetoric, Censor in Moral Philosophy, and Tutor. He attended medical lectures, investigating the function of respiration and looking to explain the various colors of blood, and conducted experiments with barometers, thermoscopes, and hygrometers in order to better understand the weather (and its potential relationship with disease). In 1663–1664, he composed Essays on the Law of Nature (in Latin), explaining that natural law, imposed by God to govern the wills of human beings for their own betterment, is not innate, but can be known by human beings on the basis of reason and sense-experience. In 1665, Charles II moved briefly to Oxford to avoid the plague that was about to sweep through London. On the basis of a recommendation, Locke was offered the chance to serve as part of a mission to Germany to prevail on the Elector of Brandenburg to remain neutral in case England fell to war with Holland. Locke's letters at the time reveal openness of mind and curiosity, and a willingness to learn about the manners and mores of foreigners (including Catholics).

In 1666, a friend asked Locke to bring some spring water for Anthony Ashley Cooper (1621–1683), later the 1st Earl of Shaftesbury, who was Chancellor of the Exchequer and a powerful man in Charles II's government. Ashley suffered from pain and jaundice, and found some relief in spring water. Locke was unable to secure the water and apologized to Ashley in person. A generous man, Ashley accepted the apology and invited Locke to stay for dinner. Thus started a friendship that lasted until Ashley's death and completely changed Locke's life.

Locke was thinking of pursuing an MD at Oxford, but, growing increasingly impatient with the demands of academic life, decided against it. He received an offer from Elinor Parry's brother to become an Anglican clergyman and (possibly) take up a position in Dublin, Ireland. Not wanting to take orders and unwilling to give up further study for a life in the church, Locke declined the offer. Though Elinor continued for a time to hope that Locke would join her in Dublin, she eventually realized that Locke was not going to give up his life in England for a life with her, and married a Richard Hawkshaw in 1670.

By 1667, Locke had joined Ashley's family at Exeter House in London, and was serving as a tutor to Ashley's son, and advising the household on medical matters. In his medical capacity, he met and interacted with Ashley's physician, Thomas Sydenham (1624–1689), from whom he learned that the best way to study any disease is by observation of its development and the effects of treating it in various ways. Locke came to see that the leading medical theories of his day, derived from Galen (130–200) and Paracelsus (1493–1541), had not been sufficiently well tested.

During the time that Locke held various academic posts at Oxford, Charles II was trying to resist repeated Parliamentary efforts to crush religious dissenters, efforts that both Ashley and Locke supported. In 1667, Locke wrote (without publishing) an Essay Concerning Toleration, in which he went back on his earlier claim that the king could regulate practices of religious worship. The next year, Ashley developed a tumor that was successfully cauterized and drained for six weeks under Locke's direction. As a result, Ashley credited Locke with having saved his life. Locke's confidence in treating Ashley reflected what he had acquired in the way of experience and testimony from numerous physicians. And it was this blend of curiosity and confidence that led him to join the Royal Society of London for Improving Natural Knowledge (founded in 1660) in 1668.

In 1669, Locke helped Ashley, who had become one of the eight Lords Proprietors of the American colony of Carolina, to draft the Fundamental Constitutions of Carolina, and served as secretary to the Lords Proprietors for the next six years. He continued work on diseases and cures therefor, but by 1670 had decided against becoming a practicing physician. Part of the reason for this was that Locke was developing what he himself took to be a “consumptive disposition,”2 probably caused by asthma or chronic bronchitis, no doubt inflamed by air pollution in London caused by the burning of sea coal. Ashley's grandson, the future 3rd Earl of Shaftesbury (1671–1713), later to become a well-known philosopher in his own right, was born in 1671, and Locke was given responsibility for his education.

At Exeter House, Locke had been involved in discussions with friends about the principles of morality and revealed religion, and realized that these questions could not be answered without a grasp of the proper compass of the human understanding. Locke recognized that many disputes are really the product of misunderstanding prompted by the failure to clarify the meanings of words. Encouraged by friends to set down some thoughts about how such disputes might best be avoided, in 1671 Locke produced two early drafts (Draft A and Draft B) of what eventually became, after 18 years of on-and-off work during his leisure hours, An Essay Concerning Human Understanding. In these drafts, Locke defended the idea that the mind is initially a blank slate, that all of the materials of knowledge derive from sensation and reflection, and that there is an important difference between knowledge, which is certain and indubitable, and belief or judgment, which is based on (greater or lesser degrees of) probability.

Locke experienced the results of political instability during the years 1672–1675. In 1672, Charles II declared war on Holland and, acting unilaterally, issued a Declaration of Indulgence protecting both Protestant non-conformists and Catholics. In the same year, Ashley became the 1st Earl of Shaftesbury and was appointed Lord Chancellor. Thanks to Shaftesbury's influence, Locke took on various paid appointments, including the position of Secretary and Treasurer of the Council of Trade and Plantations. But the conflict between Charles II and Parliament did not abate, with Charles abandoning his Declaration in the face of political opposition and Parliament passing the Test Act (requiring persons in civil or military positions to take an oath disavowing the Catholic doctrine of transubstantiation) in 1673. Charles replaced Shaftesbury as Lord Chancellor with Thomas Osborne. Fearful that Osborne's influence might lead to absolute and arbitrary government without Parliamentary check, Shaftesbury, probably with Locke's assistance, published an anonymous polemical pamphlet, A Letter from a Person of Quality, to his Friend in the Country (1675), that was condemned by the Lords and ordered to be burned.

For Locke, who was experiencing regular debilitating coughs, this was an opportune time to leave the country for a time. In the end, he spent three and a half years in France, traveling (in two separate trips) to many destinations, including Paris, Orléans, Bordeaux, Montpellier, and Lyon. Locke kept a journal, divided into four categories: philosophy, history of manners, political wisdom, and productions of art and nature. He used Latin to communicate and worked on his French. On his travels, he met several people who came to play an important role in his life, not the least of whom was Thomas Herbert (later Earl of Pembroke in 1683), who became the patron to whom the Essay is dedicated. He met the Dutch physicist Christiaan Huygens (1629–1695), the astronomer Giovanni Cassini (1625–1712), and the physician François Bernier (1625–1688), who had translated the work of the French Epicurean atomist and critic of Descartes, Pierre Gassendi (1592–1655). In 1678, he hired Sylvanus Brownower, who served him as amanuensis, secretary, and in other capacities. Locke thought of marriage, but realized that this would result in the loss of his Christchurch studentship, and would require earning a living as a physician. He came to the conclusion that marriage and death are “nearly the same thing.”3

While Locke was in France, Charles brought Shaftesbury back into the government because of his increasing popularity, in part to insulate himself against worries that his brother and heir to the throne, James, who had converted to Catholicism, would replace him and turn the country Catholic. With Shaftesbury now in a stronger position, Locke returned to England in 1679. But fearful that Shaftesbury's power and connections might make it difficult for James to succeed him, Charles dismissed Shaftesbury later that year. For two years, Charles fought with Parliament over the question of whether James should be excluded as heir to the throne or should be allowed to take the throne with limitations on his power. In 1681, Shaftesbury was arrested and charged with high treason, accused of encouraging false testimony of a “Popish Plot” to replace Charles with James. Eventually released on bail, fears that he would engage in armed rebellion because of Charles's repeated refusals to call Parliament into session led Shaftesbury to go into hiding and escape to Holland, where he died a few months later in January 1683.

During this time, Locke wrote one of the works responsible for his lasting fame, and met a person who was to become one of his closest friends, and perhaps more than that. The work was Two Treatises of Government (W5: 207–485), the first a detailed refutation of Robert Filmer's posthumously published Patriarcha: or the Natural Power of Kings (1680), which defended the divine right of kings, passed down through primogeniture from Adam's paternal right over his children and his right of dominion over the Earth granted him by God, the second a positive account of the source of governmental legitimacy in any political society formed by voluntary compact in a state of nature. The person was Damaris Cudworth (1659–1708), daughter of the Cambridge Platonist philosopher, Ralph Cudworth (1617–1688), to whom Locke was introduced in 1681 and of whom he said that there was “something more in her than is common to the rest of her sex,” and later described as “a remarkably gifted woman and one of my familiar friends.”4

In 1683, the Rye House plot to assassinate Charles and James was discovered, and warrants were issued for the conspirators. Locke began hiding and destroying papers, worried perhaps that he might be associated with the plot. A list of “damnable doctrines”5 was drawn up at Oxford, at least some of which he knew he had included in the Two Treatises. Perhaps worried about being detained on charges of treason or defamation and thence dying in detention as a result of complications deriving from ill-health, Locke fled precipitously to Holland in August. He was to remain in Holland and the United Provinces, sometimes hiding under various assumed names, for five years.

Living with the help of monetary transfers from English friends, Locke spent most of his time abroad in Amsterdam and Utrecht. He joined a semi-formal group of physicians, including Philip van Limborch (1633–1712), a Remonstrant theologian, read the occasionalist Nicolas Malebranche's Search After Truth (1674–1675) and worked on the Essay because he had a great deal of time to himself. His asthma did not trouble him as much, given that the Dutch burned peat, rather than coal. In 1684, he began drafting directions for the upbringing of a friend's son, emphasizing the importance of good habits, inculcated by praise and by example, rather than through corporal punishment, the spurring of curiosity, and the restraint of desire by means of reason. Because of his association with what were perceived as defamatory pamphlets and suspicious English expatriates living in Holland, Locke was formally expelled from Christchurch, even while he wrote to Pembroke to deny the allegations.

In 1685, Charles died and was succeeded by his brother, James II. Two failed invasions of England to depose James, led by the Duke of Monmouth and his supporters, led to the duke's execution. There is some evidence that Locke lent financial support to the invasion, even as he thought it rash. That same year, Damaris Cudworth married Sir Francis Masham, a widower 13 years her senior with several children, and went to live at Oates, near the village of High Laver in Essex, roughly 25 miles northeast of central London. There, as she reported to Locke in pining letters, life was dull and solitary. At the time, Locke was working on Draft C of the Essay, developing both the negative anti-innatist views of what would become Book I, as well as the positive theory of ideas contained in what would become Book II, and on an Epistola de Tolerantia (Letter on Toleration), refining views previously included in the Tracts on Government and the Essay Concerning Toleration. This was an apt time for Locke to be writing on the subject, given that the Catholic King Louis XIV had just revoked the Edict of Nantes (1598), which had previously provided Protestants with a measure of protection against persecution.

In the same year, Locke's first official publication, a Method of Indexing a Commonplace Book (W3: 331–349), appeared in a new periodical edited by a friend. It testifies to the obsessive compulsive side of his personality, given to the precise and efficient recording of multiple observations. Still writing to his friend about how to raise children properly, Locke recommended Aesop's Fables, Descartes's Principles of Philosophy (for their intelligibility), the learning of Latin as a living language, as well as disciplines built on observation, experiment, and reason: astronomy, geography, history, and geometry.

In 1686, Locke expanded what would become Books III and IV of the Essay, with significant discussion of the distinction between real and nominal essence and the distinction between knowledge and belief. Late in 1687, Locke approved the publication of a French abridgement of the Essay in the same journal that had published his indexing method. The initial reaction, judging by his friends' reports, was favorable. Damaris Masham, who understood the sophisticated pro-innatist views of her father's circle very well, challenged Locke in correspondence on the issue. Still voraciously interested in all matters scientific, Locke met with the microbiologist Anton van Leeuwenhoek (1632–1723), in Delft, and read (with some difficulty, given the undeveloped state of his geometrical knowledge) the newly published masterwork, Philosophiae Naturalis Principia Mathematica (1687), authored by Isaac Newton (1642–1727).

The controversy over the potential catholicization of England came to a head in 1687–1688. In April 1687, James issued a Declaration of Indulgence without Parliament's approval, eliminating a host of laws burdening both Protestant and Catholic dissenters, including the Test Act of 1673, which allowed him to bring Catholics into his government. In June 1688, James's wife gave birth to a son, assuring the real possibility of a Catholic succession. Seven important personages, including the Bishop of London, invited William of Orange, then Holland's Protestant ruler, to invade England and dethrone James. William accepted the invitation and came ashore with 15,000 soldiers in November. After numerous defections of Protestants from his army, James fled to France in December. William summoned a Convention Parliament in January 1689 to help decide who should become England's monarch. With James now no longer in power, and with a friendly Dutch Protestant in executive control, Locke accepted an invitation from one of his patrons, Lord Charles Mordaunt, to return to London in February 1689. At this point, Locke did not have a home, had lost his studentship at Oxford, did not have a job, and depended on rental income from his lands in Somerset and an annuity purchased before he left for Holland. But he had powerful and wealthy patrons, numerous well-placed friends, a reputation as a highly intelligent and fair-minded person, just-completed books to publish, and optimism about the future despite increased pulmonary congestion.

In April 1689, the Epistola de Tolerantia was published (anonymously, and in Latin) in Holland, in the same month that William and his wife, Mary, who was nearer to the succession than he, were crowned as joint sovereigns. With encouragement from William and Mary, Parliament passed the Act of Toleration, which protected Protestant (but not Catholic) non-conformists, and (in December) the Bill of Rights, which, among other things, restricted the royal prerogative by making it unlawful for English monarchs to suspend laws passed by Parliament or interfere with elections. In May, Locke was appointed to the Commission of Appeals for Excise, a salaried position, where his job was to adjudicate disputes over excise taxes. His petition to be restored to his studentship at Christchurch was approved, but he declined the invitation to return when he realized that doing so would deprive another student of his studentship. A sad letter from a newly widowed Elinor Parry, who now found herself in financial trouble with four children, led Locke to lend her some money. The Two Treatises of Government were published (anonymously) in August and an English translation of the Epistola (composed by an acquaintance) appeared in November as a Letter Concerning Toleration (W6: 3–58). The Two Treatises were (rightly) read as providing theoretical support for the legitimacy of James's removal from, and William and Mary's ascension to, the throne. In December, bearing the date “1690,” An Essay Concerning Human Understanding was finally published (under his own name). Locke recognized that the work, having been written in fits and starts over a period of almost 20 years, was too long and repetitive, but described himself as “too lazie, or too busie to make it shorter” (Essay, The Epistle to the Reader: 8).

In 1690, Locke stayed with the Mordaunts on the outskirts of London to avoid the pollution that exacerbated the inflammation of his lungs, and worked on a reply to a recently published attack on his Epistola by Jonas Proast (1640–1710), chaplain of All Souls College, Oxford. A Second Letter Concerning Toleration (in English, W6: 61–137) was published in May, under the pseudonym “Philanthropus” (lover of humanity). Locke visited Oates for the first time in June, and clearly enjoyed his visit, because he moved himself along with all of his possessions (including a library of 2000 volumes that would eventually grow to almost 4000 at the time of his death), which had been scattered amongst friends during his time in Holland, to Oates in 1691. Locke paid for room and board for himself and his servant, Sylvanus, and undertook to shape the education of Francis and Damaris's five-year-old son, “little Frank.” The Mashams clearly treated Locke as a valued member of the family: Locke ran errands, gardened with Damaris, and helped the household deal with various ailments.

Locke's interest in economics, which had developed from the time of his attachment to the Shaftesbury household, led to the (anonymous) publication of Some Considerations of the Consequences of the Lowering of Interest, and Raising the Value of Money (W5: 1–116) in 1691. The controversy concerned whether it was better or worse for the economy for the rate of interest on commercial loans to be lowered from 6% to 4% and for silver and gold coins, which were being “clipped” for the precious metals of which they were made, to be devalued. (Locke opposed both the lowering of interest rates and the devaluation of the currency.) That same year, Robert Boyle died, and Locke found himself editing Boyle's unfinished General History of the Air for publication. He also started making obsessively regular weather observations at Oates, and initiated what turned into a 12-year project of translating Aesop's Fables from Latin into English.

Faced with continued public criticism of his work on toleration, Locke could not resist penning an extraordinarily lengthy response to Proast's reply to his Second Letter, and A Third Letter for Toleration (W6: 141–546) was published in 1692. That same year, Locke came across a just-published book, Dioptrica Nova, by the Irishman William Molyneux (1656–1698), a Fellow of the Royal Society who had some complimentary things to say about the Essay. Locke wrote to thank Molyneux, and this initiated an intellectually fruitful long-distance friendship (eventually leading Molyneux to travel to Oates to spend five weeks with Locke just before his sudden and unanticipated death upon his return to Dublin in 1698) that did much to shape subsequent editions of the Essay. In the course of their correspondence, Molyneux asked Locke to say more about two important matters: (i) the “principium individuationis,” or principle that establishes the identity of objects over time, and (ii) liberty and necessity (passing on questions and objections from William King, the Bishop of Derry), the worry here being that Locke was making “all sins to proceed from our understandings,”6 rather than from our wills. Molyneux also sent Locke a hypothetical case that came to be known as “Molyneux's Problem”: whether a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere, so as to tell which is which, could, if made to see, distinguish between them purely by sight (Locke's answer was “no”; see E II.ix.8: 146).

Collecting his thoughts (penned over the course of nine years) about the best way of educating children, Locke published Some Thoughts Concerning Education (W9: 1–205) anonymously in 1693. In response to Molyneux's questions, Locke drafted a lengthy extension to the Essay's chapter “Of Power” (E II.xxi) on the will and freedom of action, an additional chapter (E II.xxvii), “Of Identity and Diversity,” to propose his own principle of individuation and its application to personal identity, and a paragraph discussing Molyneux's Problem (E II.ix.8), among other (numerous, smaller) changes.

The second edition of the Essay was published in May 1694. Later that same year, Locke started thinking very seriously about Christianity, and in particular about what makes someone a Christian. His reason for focusing on this was that the fewer the theological doctrines adherence to which rendered someone a Christian, the less conflict among Christians would be generated by the existence of a variety of Christian practices and modes of worship. In the end, Locke came to the view, published anonymously in The Reasonableness of Christianity, as delivered in the Scriptures (1695, W7: 1–158), that the definition of a Christian is someone who believes that Jesus is the Messiah. A third edition of the Essay, involving minor alterations to the second edition, was published in 1695, and Locke was appointed Commissioner of Greenwich Hospital, to oversee the care of sailors in need of medical attention.

The Reasonableness included no mention (or serious discussion) of central Christian doctrines: the Trinity (three divine persons, God, the Son, and the Holy Spirit, in one substance), the Incarnation (the unity of human nature and divine nature in one person, Jesus), original sin, and bodily resurrection. This led several Anglican clergymen, notably a certain rather acerbic John Edwards (1637–1716), to worry that the author of the Reasonableness was a Socinian (generally speaking, one who denies these doctrines) and, indeed, because of this, a near-atheist. Locke became embroiled with Edwards in an increasingly acrimonious exchange of public letters (first in a Vindication of the Reasonableness of Christianity, etc. from Mr. Edwards' Reflections (1695, W7: 159–180), then in a Second Vindication of the Reasonableness of Christianity (1697, W7: 181–424)), defending himself, sometimes with sarcasm and invective, against the malicious accusation that he was engaged in a Socinian plot.

In December 1695, Locke was appointed Commissioner for Trade, another salaried position, this one devoted to the investigation of potential improvements to trade and manufacturing, the reduction of unemployment, and the administration of colonial plantations. This position took up a great deal of Locke's time (at least three long meetings per week, sometimes more), at a time when his health was worsening in part because the meetings were in London. In 1696, Locke became aware of remarks that the mathematician and philosopher Gottfried Wilhelm Leibniz (1646–1716) had made about the Essay. As he told friends, Locke did not think much of Leibniz's criticisms (particularly the criticisms of Locke's views on innatism), which explains why Locke's exchanges of papers with Leibniz never led to any serious philosophical correspondence between them.

By 1697, Locke had given up any serious study of “physic,” and was concentrating on his public service, possible alterations to the Essay, and defenses against published attacks on his work. In A Discourse in Vindication of the Doctrine of the Trinity (1697), Edward Stillingfleet (1635–1699), Bishop of Worcester, added a few criticisms of the Essay connecting Locke to skepticism about the external world, to Socinianism, and to unitarian doctrines recently defended by the free-thinker and satirist John Toland (1670–1722), in Christianity Not Mysterious (1696). Eager to defend himself against these charges and to distinguish between his views and Toland's, Locke published A Letter to the Right Reverend Edward Lord Bishop of Worcester Concerning some Passages … in a late Discourse of his Lordship's in Vindication of the Trinity (W4: 1–96) in 1697. In part because of his declining health and the many matters that engaged his attention, Locke offered to resign from the Board of Trade, but in the end was prevailed on to stay for what ended up being another three years. Stillingfleet, like Edwards, was not done. This led to further public letters, Mr. Locke's Reply to the Bishop of Worcester's Answer to his Letter, etc. (1697, W4: 97–189), which included an appendix replying to the criticisms of Thomas Burnet (1635–1715) about the voluntaristic aspects of Locke's moral philosophy, and Mr. Locke's Reply to the Bishop of Worcester's Answer to his Second Letter (1698, W4: 191–498), which was “too long” even by Locke's own standards.7 In these years, Locke also drafted an unfinished chapter that he meant to include in the Essay, “Of the Conduct of the Understanding” (W3: 205–289), in which he catalogued the different ways in which the understanding might be misused, an essay on poverty, in which he defended public support for disabled adults but houses of correction and vocational schools for the able but idle poor and their children, and a short summary of current scientific theory, Elements of Natural Philosophy (W3: 301–330), for his 12-year-old tutee, “little Frank” Masham.

In 1700, Locke added two new chapters, “Of the Association of Ideas” (E II.xxxiii) and “Of Enthusiasm” (E IV.xix), as well as a significant number of smaller changes, to the fourth edition of the Essay. Citing ill-health, including what was now poor circulation in his legs, Locke resigned from the Board of Trade (though not from the Board of Appeals for Excise, which met infrequently). After an illness in 1702, he was left with deafness in his left ear. He spent much of his time corresponding with friends, including important letters on free will with van Limborch and a complimentary letter of thanks (followed by gifts of books and money) to Catharine Trotter (1679–1749), a convert to Catholicism who had written novels and plays, but also, at the age of 23, A Defence of Mr. Lock's An Essay Concerning Human Understanding (1702). Locke was asked for, and wrote, numerous letters of recommendation, was constantly asked for medical advice, and continued his weather observations. He began a close study of St Paul's Epistles, which eventually led to the posthumous publication of A Paraphrase and Notes on the Epistles of St. Paul (1705–1707). He met, and was very much taken by, the young and dynamic Anthony Collins (1676–1729), who would eventually make a name for himself as a free-thinker. And he oversaw the publication of his translation of Aesop's Fables.

In 1704, Locke was told that some Oxford colleges were discussing the possibility of banning his books, because students were relying on the Essay instead of spending their time studying Scholastic logic and metaphysics (perhaps the ultimate compliment, though Locke did not take it well). Unable to stop himself, despite his bronchial condition, he penned A Fourth Letter for Toleration (W6: 547–574), which remained unfinished at his death. He died peacefully at Oates, surrounded by friends, letting them know that “this life is a scene of vanity that … affords no solid satisfaction but in the consciousness of doing well and in the hopes of another life.”8 His estate was valued at a little over £12,000, a significant sum, but he was buried in a plain wooden coffin (at All Saints' Church in High Laver) because the money for additional adornments would be better spent “covering … four honest poor labouring men of the neighborhood … with a coat and pair of breeches of cloth, a hat, a pair of shoes and stockings.”9


1 Roger Woolhouse, Locke: A Biography. Cambridge: Cambridge University Press, 2007, 45.

2 Woolhouse 2007, 96.

3 Woolhouse 2007, 149.

4 Woolhouse 2007, 175, 299.

5 Woolhouse 2007, 193.

6 Woolhouse 2007, 320.

7 Woolhouse 2007, 403.

8 Woolhouse 2007, 452.

9 Woolhouse 2007, 460.

further reading

Cranston, Maurice, John Locke: A Biography. London: Longman, 1957. Reprinted by Oxford University Press, 1985.

Marshall, John, John Locke: Resistance, Revolution, and Responsibility. Cambridge: Cambridge University Press, 1994.

Woolhouse, Roger, Locke: A Biography. Cambridge: Cambridge University Press, 2007.

chapter 2

the nature and role of ideas