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  • Writer's pictureJon Hersey

John Locke: The Father of Liberalism

Author's note: This article was originally published at The Objective Standard.

Some have said that the history of the Western world is a battle between the ideas of Plato and those of Aristotle, between the otherworldly and the this-worldly, between the mystical and the rational.[1] The Enlightenment was an age when the Aristotelian approach of observation and logic generally prevailed, when a great many thinkers—for the first time since ancient Greece—truly prized their minds as the means by which to understand and shape the world. Isaac Newton discovered mathematical principles governing natural phenomena, Benjamin Franklin turned disparate observations about electricity into a unified scientific theory, Captain James Cook explored distant lands, Denis Diderot organized a mass of new knowledge in the world’s first encyclopedia. Instead of basking in thoughts of the glory of an alleged afterlife, a number of great men turned their focus to the here and now, toward making this world as good a place as possible for human life.

Some embraced this scientific mind-set and applied it to understanding man himself, his means of knowledge, ethics, and the origin, purpose, and proper structure of government. The result of their efforts was most eloquently expressed in the Declaration of Independence: “We hold these truths to be self-evident, that all men are created equal,” wrote Thomas Jefferson, that they have “certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. — That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed.” The distinctive social and political philosophy of the Enlightenment enshrined liberty, so the system of thought that men developed to support and defend it became known as liberalism.

Importantly, however, this political philosophy did not originate with Jefferson or his contemporaries. As Jefferson wrote, “the object of the Declaration” was “not to find out new principles, or new arguments, never before thought of,” but rather “to be an expression of the American mind.” “[A]ll its authority,” he conceded, “rests then on the harmonizing sentiments of the day.”[2] And as he readily pointed out, one of the primary shapers of the American mind was John Locke.[3] Locke (1632–1704) was at the forefront of Enlightenment thinkers who advanced an experimental, this-worldly approach to knowledge, science, and philosophy. Although he was not the first to advance a theory of natural rights, his defense of rights was the most systematic, clear, and comprehensive—and, consequently, the most influential.[4]

Sons of Liberty leader Samuel Adams bolstered his arguments for the rights of American colonists with near direct quotations of Locke.[5] Alexander Hamilton chastised an adversary for his apparent ignorance of natural rights theory and recommended that he read Locke.[6] John Adams cited Locke as an inspiration for his “revolution-principles,” which he said were “the principles of nature and eternal reason” and constituted a rational alternative to docile obedience and bloody anarchy.[7]

Adams also was influenced deeply by Locke’s ideas about the nature of the mind and our means of acquiring knowledge. So was Benjamin Franklin, who commemorated Locke as “the Newton of the Microcosm” and who relied heavily on Locke’s ideas about education, history, rhetoric, and law in his efforts to establish Philadelphia Academy (known today as the University of Pennsylvania).[8]

Indeed, if Jefferson or any other writer of the time had intended to express not the “American mind,” but the Western mind or the Enlightenment mind as such, he’d be hard pressed to articulate its “harmonizing sentiments” without invoking the ideas of John Locke. If we want to advance the Enlightenment and live in it today, we must understand Locke’s ideas.

In Pursuit of Useful Truths

Locke so well encapsulated the Enlightenment mind because he passionately pursued any and all knowledge that could be used to enhance human life and happiness. As a friend of his said, what Locke “chiefly loved” were “truths that were useful, and with such fed his mind.”[9]

He was first a student, later a lecturer and tutor at the University of Oxford, where he befriended the great chemist Robert Boyle. Together, they conducted experiments on, among other things, the nature and function of blood and of air. Locke speculated that air temperature and weather somehow were causally connected to the spread of disease. Using a barometer, a thermoscope, and a hygrometer, he tracked weather and temperature throughout much of his life, hoping that others around the world would do the same and that one day someone would integrate this data to explain how diseases spread.[10]

When Locke traveled to France in the company of a diplomat, he gave himself the standing order to note “what things we find amongst other people fit for our imitation, whether politic or private wisdom,” specifically “any arts conducing to the convenience of life.”[11] He took notes on making wine, olive oil, soap, and turpentine; on rearing silk worms and recovering sea salt; on cultivating olives, grapes, plums, figs, and oranges; and on preparing various foods. An acquaintance reflected that Locke would question all types of craftsmen and “would find out the secret of their art, which they did not understand themselves, and oftentimes give them views entirely new, which sometimes they put in practice to their profit.”[12]

While living in Holland, he met the famous microscopist Antoine van Leeuwenhoek, whose instruments the two men used to magnify and study several biological specimens.[13] He also conducted experiments on the behavior of water in a vacuum and, while in Paris, made observations of the Moon at the Royal Observatory. He corresponded with great minds all over the world, and, thinking it would be helpful if they all used the same standards of measurement for length, invented and proposed a system based on what he called the “philosophical foot.”[14]

He struck up a close friendship with Isaac Newton after publishing a review of his Philosophiæ Naturalis Principia Mathematica in a Dutch journal.[15] And he was mentored by the groundbreaking physician Thomas Sydenham, whose Observationes Medicæ became a staple text for physicians for two centuries and who became known as “the English Hippocrates.” Medicine became Locke’s greatest passion. “Length of life, with freedom from infirmity and pain,” he said “is of so great concernment to mankind that there can scarce be found any greater undertaking than the profession to cure diseases.”[16]

In all of these fields and many more, Locke relentlessly pursued useful knowledge. He took such voluminous notes on so many subjects that he eventually had to invent a handy method for indexing them so that he could easily look up what he’d previously written.[17] The depth and breadth of Locke’s mind led one friend to conclude that he was a rare breed, a “homo versatilis ingenii [a man of versatile mind], and fixed for whatever you shall undertake.”[18]

To achieve such breadth and depth of thought, Locke held one principle supreme.

The Importance of Intellectual Honesty

Because Locke aimed to discover useful knowledge, he held and repeatedly stressed that we must follow the truth wherever it leads, even if doing so reveals that earlier we had been wrong. There’s no sense in digging in one’s heels to defend a position in an attempt to save face.

He invited frank criticism of his work. For instance, when a Dublin savant, William Molyneux, wrote to Locke with some thoughts on improving his Essay Concerning Human Understanding, Locke urged him to offer his feedback freely. “I flatter myself that I am so sincere a lover of truth,” he wrote, that “I count any parcel of this gold not the less to be valued . . . [b]ecause I wrought it not out of the mine myself.”[19] He later said that the aim of his Essay was “only truth so far as my shortsightedness could reach it, and where I have misstated it in part or in whole I shall be glad to be set right.”[20] As one of Locke’s editors, Kenneth Winkler, observed, Locke’s choice of title for that work also reflects this sentiment.[21] Although we now use the term “essay” to refer to just about any work of nonfiction, in Locke’s day it signified a work along the lines of what we might today call a hypothesis, intended to explore and clarify a subject—without the implication that the author was pronouncing a settled truth or even his own final, fully considered view.

Locke stressed the importance of intellectual honesty in part because of the intellectual climate of his day.

Against ‘Learned Gibberish’

Locke’s passion for curing disease never abated, but his admittedly hodgepodge life did not accommodate a medical career.[22] Nevertheless, he became increasingly convinced that one particular ailment had stultified human progress, making it the most high-leverage target.

Christian Aristotelians of Locke’s day, known as Scholastics, accepted the content of many of Aristotle’s conclusions, while rejecting his observation-based method. They embraced his conclusions in the form of religious dogma.[23] On a short trip abroad, Locke was lured into a dispute with some “young monks” who argued eagerly for Aristotle’s idea of the existence of prime matter (matter that has no form and so can become any substance). They couldn’t point to any evidence in support of this view. Yet, Locke said, they behaved “as if they were to make their dinner on it.”[24] He disdained the “artificial ignorance and learned gibberish” of such debate, which he encountered repeatedly.[25]

Locke applauded the fact that intellectuals increasingly were embracing experimental natural philosophy (what we today call “science”), which proceeded on the basis of observation and experiment—the method of Aristotle. Nevertheless, much of the intellectual world was still dominated by Scholastics and speculative natural philosophers, who eschewed or downplayed the significance of sensory evidence and who focused instead on abstract principles—the method of Plato. Descartes, for instance, had spun from thin air his famous vortex theory, which held that celestial bodies move in a massive network of whirling fluid. Similarly, in order to explain how the biblical flood could have happened given the earth’s insufficient volume of water, Thomas Burnet posited that the earth once had a shell like that of an egg, which cracked and submerged into the water below, then gradually resurfaced.[26] As a friend later recalled, Locke spurned these “learned hypotheses” as babble, “which, having no relation to the nature of things, are fit for nothing at the bottom, but to make men lose their time in inventing, or comprehending them.”[27]

In 1671, he and some friends gathered to discuss the roots of morality but were soon puzzled by questions about how humans gain knowledge about anything. The things that people believe, Locke later wrote, are “so various, different, and wholly contradictory; and yet asserted somewhere or other with such assurance and confidence . . . [we] may perhaps have reason to suspect, that either there is no such thing as truth at all; or that mankind has no sufficient means to attain a certain knowledge of it.”[28] Locke realized that what was holding so many people back and setting them astray was that they did not follow a rational method for gaining knowledge.

He soon drafted some thoughts on the subject for consideration and discussion among his friends. Over the next eighteen years, in fits and starts, he would continue to refine his answer to one of the greatest problems men faced: the need for epistemic grounding and rigor, for a means of gaining useful knowledge while avoiding fruitless diversions and airy speculation. The result was his landmark work in philosophy, An Essay Concerning Human Understanding. It was a work of profound insight that helped to correct many errors of prior thinkers and to launch the field of psychology. In essence, it defended the Aristotelian, rational, scientific approach to knowledge.

Locke’s Essay Concerning Human Understanding

A generation before Locke, Descartes resurrected the Platonic notion that we are born with innate ideas. He argued that although certain ideas “do not depend on my will, it does not follow that they must come from things located outside me.” Instead, “there may be some other faculty not yet fully known to me, which produces these ideas without any assistance from external things; this is, after all, just how I have always thought ideas are produced in me when I am dreaming.”[29] He told a correspondent, “I am certain that I can have no knowledge of what is outside me except by means of the ideas I have within me.”[30] If we want knowledge, he held, we must begin not by examining the testimony of the senses, but by considering our ideas, especially those baked into our minds by our creator. To Locke—who assisted Boyle with chemical experiments, worked as a doctor, and corresponded with cutting-edge scientists the world over—nothing could have been more nonsensical than the notion that we should begin our search for knowledge by contemplating so-called innate ideas.

If certain ideas were innate, Locke argued, they would necessarily be accepted by all, but there are no such universally accepted ideas. Among Locke’s many interests was his passion for travel literature: the accounts of explorers who had journeyed to far-off regions and experienced exotic cultures. He had a large collection of such literature, which he’d studied intently. So he had no trouble pointing out that even the most uncontroversial ideas that could be offered in support of the theory of innate ideas were not even known by the entire populations of some countries, never mind accepted. Nor were they known by the children or mentally handicapped right there in England. Moreover, if any idea were universally accepted, that would not prove it innate. It could simply be that the idea was so obvious that no one who understood it could fail to accept it.

Contrary to proponents of the theory of innate ideas, Locke held that at birth, the mind is like a sheet of white paper, and the only thing that writes upon the paper is experience. All knowledge, everything we come to learn, ultimately derives from perception of the world, which Locke referred to as sensation. Only once we’ve perceived a great many things can we reflect on this content, examine its implications, and use it to derive further knowledge. And only when we’ve accumulated ideas in memory can we combine them in new ways and imagine things we’ve never experienced.

Locke saw the need to answer an objection that had roots in Ancient Greece and proponents among his contemporaries—namely, that the senses often don’t give us knowledge of reality. They pointed out that sensory experience is highly variable, both from one person to the next and even for the same person under different circumstances. For instance, the color of a rose is different depending on the lighting and the condition of one’s eyes. Likewise, the scent of a rose can differ from one person to another—or even for the same person at different times. Thus, we must begin any search for truth by disregarding the testimony of the senses. As Descartes put it, “Whatever I have up till now accepted as most true I have acquired either from the senses or through the senses. But from time to time I have found that the senses deceive, and it is prudent never to trust completely those who have deceived us even once.”[31]

Locke understood that this problem had so long confused thinkers because it packaged something true with something false. He recognized that certain perceptual qualities vary under certain circumstances, but he did not regard this as grounds for repudiating the senses altogether. For instance, although the color or scent of a rose may differ depending on the circumstances, we all perceive the same general shape and texture.

The best scientists of the day, including Locke’s friend Boyle, speculated that all material entities ultimately were made up of tiny, imperceptible corpuscles or atoms—a theory (also with roots in Ancient Greece) that became known as the corpuscularian hypothesis. In the introduction of his Essay, Locke promised that he would “not at present meddle with the physical consideration of the mind . . . or by what motions of our spirits or alterations of our bodies we come to have any sensation by our organs.” He realized that the corpuscularian hypothesis was just that, a hypothesis about the physical nature of things with as yet no more basis in sensory evidence than the speculative theories he rejected. Microscopes were not powerful enough to reveal the smallest particles of matter, nor was Locke optimistic that a science of corpuscles was on the horizon.

Even so, once he began to lay out his arguments in the Essay, he relied on the corpuscularian hypothesis to answer those who were skeptical of the senses. He postulated that the reason we perceive certain qualities of objects as stable—namely, bulk, figure, number, and motion—is that these are qualities of corpuscles themselves, and our senses reveal these qualities to us just as they are. This is why, for instance, all people perceive a rose as having the same general shape.

By contrast, he said, our experience of a rose’s color, taste, and smell vary because these are notqualities of its corpuscles that our senses simply reveal to us. Rather, they are produced by the interaction between the rose’s corpuscles and our sense organs. Different people (or even the same person under different circumstances) may experience a rose’s color, taste, and smell differently, because variations in the causal chain produce varying results. Locke called these varying qualities—which included an object’s color, taste, smell, or sound—“secondary qualities,” and the stable qualities that we perceive “as they actually are” he called “primary qualities.”

Locke held that this distinction enables us to account for perceptual variation while still defending the validity of the senses—at least in regard to primary qualities. His position also implied that our experiences of secondary qualities are illusory in that they don’t reveal to us reality “as it really is.” They don’t directly convey to us anything about the nature of the supposed underlying corpuscles.

Nonetheless, he held that because secondary qualities arise from an object’s primary qualities, they do provide a sort of approximate knowledge sufficient for conducting our lives. As he put it:

’Tis of great use to the sailor to know the length of his line, though he cannot with it fathom all the depths of the ocean. ’Tis well he knows, that it is long enough to reach the bottom, at such places, as are necessary to direct his voyage, and caution him against running upon shoals, that may ruin him. Our business here is not to know all things, but those which concern our conduct.[32]

Seeds of Skepticism

Locke made admirable strides in explaining our means of knowledge. Yet, despite his emphasis on reason and experience, he was a devout Christian and held that our creator “has afforded us only the twilight.” God has purposely left our minds in a “state of mediocrity” in order to make us “sensible of our short-sightedness and liableness to error.”[33]

These supposed limitations on our knowledge dovetailed both with Locke’s desire to dissuade speculative natural philosophers of their “learned gibberish” and with his thoughts on secondary qualities. Regarding the latter, he said that we experience the rose as appearing red and smelling sweet, but without an understanding of its corpuscular substructure, we can’t say why these things are true—and thus we lack verifiable knowledge that they are. So, although he advocated that men go by the testimony of the senses, he simultaneously held that much of our sensory experience is dubious—suspended in a sort of epistemic limbo.

Further, Locke accepted Descartes’s idea that we don’t perceive reality directly. The only things we are directly aware of, Locke held, are our ideas, which are the constant intermediary between us and the world. This raised the obvious question: If we are aware only of our ideas, how can we be certain that they’re anything like the world? In order to compare two things, we must have some access to each. But if the totality of our awareness consists of our ideas, we are cut off from the material world—inescapably confined to our own minds. Locke did not accept this skeptical conclusion, nor did he provide a solution to the problem.

Within a decade of Locke’s death, Irishman George Berkeley proceeded to turn this bug of Locke’s system into the chief feature of his own, promoting skepticism with the publication of his Three Dialogues between Hylas and Philonous. Is it possible, Berkeley asked, that all of our ideas are caused not by our interaction with an external world but by a superior being’s direct manipulation of our minds? Locke had foreseen such a question and answered, in effect, that no one could be so skeptical. Berkeley, however, was. He held that there is no material world. There is only us and God, who causes all of the ideas in our minds directly.

Less than seventy years after Berkeley’s Three Dialogues was published, Prussian philosopher Immanuel Kant published his Critique of Pure Reason, which likewise distilled problematic elements of Locke’s ideas down to pure skepticism. Locke’s primary/secondary quality distinction implied that there is the world as it appears to us and the world as it really is, and his premise that we are aware only of our ideas meant that we are incapable of accessing the world directly. Kant embraced and amplified these dichotomies, postulating not just different perspectives on the same, unified world, but two entirely separate realms: a universe of appearances in which we experience and live our lives, and a universe of actual things in themselves—from which we are cut off and about which we can know nothing.[34]

Thus, although Locke had no way of knowing it, later philosophers would turn parts of his philosophy against him—and against all advocates of reason—arguing that man’s mind is forever cut off from reality as it really is.

Yet, despite the fact that Locke left many philosophic problems unsolved, he was instrumental in reviving a rational, Aristotelian approach to knowledge and countering the Platonism of his day. His epistemology was a major improvement over that of the Scholastics and of Descartes, and it fueled important philosophic and cultural advances.

Deal with Men by Reason, Not Force

In his thinking about man’s mind, Locke hit upon an epistemological principle that would have profound political consequences, but not before he reversed some of his views.

You’ve heard the saying, “If you’re not a liberal at twenty, you have no heart. If you’re not a conservative at forty, you have no brain.” Locke’s progression went in the opposite direction—from conservatism (i.e., adherence to traditional ideas) to liberalism (in the classical sense of the term).

In the time between his tenth and thirtieth birthdays, England fought three civil wars, executed a monarch, exiled another, established a commonwealth, replaced it with a protectorate led by Oliver Cromwell, then restored the monarch it had exiled (Charles II). Having grown up among such chaos—largely resulting from disputes over religious beliefs—Locke concluded that different sects were entirely incapable of living peacefully together, and so they needed a strongman to impose religious conformity.

Shortly after the restoration of Charles II, Locke wrote his Two Tracts on Government (not to be confused with his Two Treatises), arguing that when men form a government, they agree to give up their liberty, that the obedience demanded by Christ must be directed to the magistrate, who is properly granted complete and unquestionable authority over all of his subjects, and over all things, civil and religious. He held that without such an “orderly council,” anarchy would reign. In other words, Locke’s Two Tracts upheld traditional views about religion and government and thus were as conservative as can be.[35]

The only hint of liberalism in Locke’s Two Tracts was the idea that the magistrate—rule as he may over all aspects of man’s outward life—“cannot cast minds or manners into one mould.”[36]Although the king could force men to obey, he could not force them to think one way or another. So, according to Locke’s Tracts, men are free to believe as they will, even if they are forbidden to act on certain beliefs.

Given the brutal intolerance Locke had witnessed while growing up in England, he was understandably awestruck when, about five years after writing his Two Tracts, he visited Cleves in Germany, where Lutherans, Calvinists, and even Catholics lived and worshipped in peaceful community. Two years later, an anonymous pamphlet in Latin, titled “Epistola de Tolerantia,” was published and quickly circulated among intellectuals, garnering many strong supporters—and many critics. Today, we know that the author of this pamphlet was John Locke, as some surmised during his lifetime. But although he saw this “Letter on Toleration” through subsequent publication in English, he swore his publisher to secrecy and never acknowledged his authorship.[37]

The reason for religious conflict, Locke here acknowledged, was not that those of different religious persuasions could not live together in peace. Rather, the reason was that some tried to force their views down the throats of others. No religious belief—nor any other type—can be “propagated by force of arms,” he wrote, because

such is the nature of the understanding, that it cannot be compelled to the belief of anything by outward force. Confiscation of estate, imprisonment, torments, nothing of that nature can have any such efficacy as to make men change the inward judgment that they have framed of things.[38]

Forcing men to attend this or that church, to participate in this or that service on the grounds that it would save their souls, is entirely pointless. “I may be cured of some disease by remedies that I have not faith in,” Locke argued, “but I cannot be saved by a religion that I distrust and by a worship that I abhor. It is in vain for an unbeliever to take up the outward show of another man’s profession.”[39]

Further, he argued that magistrates are empowered to punish “those that violate any other man’s rights” but that such civil power “neither can nor ought in any manner . . . be extended to the salvation of souls.”[40] My soul is not the business of government, he held. And on the other hand, churches have no “jurisdiction in worldly matters” and ought never to be allowed to “call in the magistrate’s authority to the aid of their eloquence or learning.”[41] In other words, Locke held that the nature of man’s mind necessitates the clear and total separation of church and state.

That said, in Locke’s day the Catholic church arrogated to itself the authority to demand the deaths of dissenters (as do certain Muslims today). So although he argued for religious freedom, he held that because Catholics were so often violent, they had forfeited this freedom. Likewise, he believed that morality and civility were possible only to people who believed in God, so he concluded that atheism should be outlawed.

Fortunately, Thomas Jefferson later realized that Locke’s principle of church/state separation is perfectly compatible with any and all views so long as government protects rights and deals with aggressors, whether Catholic, atheist, or otherwise. So, he recast the idea without Locke’s exceptions. Arguing for absolute religious freedom, he wrote, “The legitimate powers of government extend to such acts only as are injurious to others. But it does me no injury for my neighbour to say there are twenty gods, or no god. It neither picks my pocket nor breaks my leg.”[42] Thus, Locke’s insight became the basis for Jefferson’s Virginia Statute for Religious Freedom, the thrust of which James Madison later incorporated into the First Amendment of the United States Constitution.

In time, Locke would further develop his liberal view of government—with limits imposed by man’s nature—and it would bring him into conflict with other thinkers and leaders of his day.

In 1679, James II, a Catholic, was poised to inherit the English throne, and his wife had just become pregnant, which raised the material possibility of a Catholic dynasty. The English were well aware that, across the channel in France, the absolutist Catholic monarch Louis XIV had concentrated power, proclaiming “l’état, c’est moi (the state is me).”

Locke’s friend and patron Lord Shaftesbury led the Whig party in an attempt to preserve parliamentary power by excluding any Catholic from acceding to the English throne. Living at Shaftesbury’s estate during this “exclusion crisis,” Locke penned his Two Treatises of Government, but he kept the manuscripts hidden, distributing only partial copies to a few friends.

Soon, some of Shaftesbury’s associates were arrested and, under pressure, told authorities that he was plotting to overthrow the monarchy. He was forced to flee from England to Amsterdam, where he soon fell ill and died. Shortly thereafter, a contemporary of Locke’s, Algernon Sidney, was executed for publishing ideas similar to those in Locke’s hidden manuscripts of the Two Treatises.

As more and more of Locke’s friends and acquaintances were arrested or questioned by authorities, he thought it prudent to flee to Holland, where he would spend the next five years. Neither his Two Treatises nor his Essay would be published until after his return to England.

Locke’s Two Treatises was, in part, an answer to two writers who had sought to justify political absolutism (i.e., the doctrine of unlimited power vested in a monarch or dictator): Robert Filmer and Thomas Hobbes.

Filmer deduced from the Bible a defense of absolute monarchy. He argued that God gave Adam absolute dominion over Eve and their children, that all subsequent fathers inherited this dominion, and that at some point the eldest among them was made a monarch and given dominion over every living being. To explain the large number of monarchs in his day, Filmer argued that several events described in the Bible caused kingdoms to split. And, after drawing out this line of argument, he attempted to cover his bases by claiming—despite his rationale for monarchy—that any sitting monarch is a legitimate monarch because he is a monarch. Locke apparently took pleasure in picking apart Filmer’s shoddy logic; the entire First Treatise is a refutation of Filmer.

Hobbes, far less antiquated in his thinking than Filmer, argued, like Locke, that political relations derive from man’s nature. But he said that in a state of nature—in a pre-political society—man is essentially a wild beast, that life is a “war of every one against every one.”[43] Every man’s self-interest demands that he pillage and dominate others. The strongest conquers all and allows them to live only if they obey his every command. His might equals right; there is no other source of it. And Hobbes argued that such subjugation actually benefits people; it gives them a strongman to defend them against foreign invasion, and it reduces the bloody warfare that is rampant under anarchy. He would have agreed wholeheartedly with the ancient Greek thinker Heraclitus, who wrote, “War is the father of all and king of all, and some he shows as gods, others as humans; some he makes slaves, others free.”[44]

Locke did not disagree that this was in fact how some people lived. But, he thought, what men should do is an altogether different question than what they have done. Men are not necessarily wild beasts, he argued. They are beings endowed with a rational faculty who therefore have the potential to be civil.[45] By using their reason, men are capable of discovering a “law of nature,” which tells them that all men—despite differences in strength, intelligence, moral fortitude, and so forth—are fundamentally equal in one respect: each has “a right to [his own] preservation,” a right to use and preserve his own mind, body, life.[46]

And, by extension, man has a right to the product of his effort. Because he has a right to his own sweat and blood, because he has a right to his own body and therefore his own labor, he necessarily has a right to what he produces. He may choose to work and produce goods or services. And he may choose to trade the product of his labor with others for their goods, services, or money. But no one can rightfully force him to work or deprive him of the products of his effort.

And, said Locke, when a man mixes his labor with some as-yet unowned stretch of earth, when he improves this unowned land—perhaps by cultivating it for crops or by building a house on it—that land, that property becomes his by right. Thus, his right to life is the root of his right to property.[47]In Locke’s view, all rights ultimately derive from the fact that man has a right to his own preservation.[48]

Given these rights, Locke held that in the state of nature, each man has a right to defend himself from thieves and attackers. If you attack me, you demonstrate that you don’t recognize rights and that you are (as Hobbes held) a beast—an animal that cannot be reasoned with and so must be dealt with by force. Men have the right to defend their property and person, including the right to kill an attacker.[49]

However, a state of nature in which every man is judge, jury, and executioner is filled with, as Locke quaintly put it, “inconveniences.”[50] Of course, the situation is worse than inconvenient for the man who is outmatched and incapable of defending his rights (one reason why anarchism is untenable).[51] A state of nature leaves open the possibility of the injustices that Hobbes thought inescapable. Men in such a state, who have no common judge to turn to, says Locke, must go toe-to-toe with their aggressors and must hope that they come out on top. Plus, if each man is judge, jury, and executioner in defense of his rights, each necessarily will be prejudiced in his own favor, which also could lead to injustice and great disparities in punishments and reparations.

So, Locke said that in order to protect their rights, reasonable men agree to delegate certain powers and responsibilities to a man or body of men. They delegate decisions on just penalties and the retaliatory use of force—and they do so in order to better protect their rights.[52] Thus, he held, government derives its just powers from the consent of the governed.

When government strays from this purpose, when it perpetrates abuses and infringes the rights it is supposed to protect, the governed may rightfully rescind their consent, abolish their government, and either return to a state of nature or establish a new government.[53]

Although others had voiced similar ideas about natural rights, Locke was revolutionary in that his political views were rooted in an essentially Aristotelian epistemology, which enabled him to undercut the fundamental premise of most tyrannies: the idea that some men are inherently superior to others. Plato’s theory of innate ideas implied the need for “elites” with the requisite brain power and leisure time to sit in solitude and tease out hidden truths. The common man—wrapped up in the affairs of life—had no time or capacity for such leisurely reflection and so was “confined” to the “false testimony of the senses.” Thus, Plato’s theory—a favorite of despots throughout history—led inexorably to the view that philosopher kings had a monopoly on knowledge and so should rule over others.[54]

By refuting the theory of innate ideas, Locke toppled any pretense at such a monopoly. Men can grasp reality via their senses sufficiently to run their own lives, he argued, and they should be free to do so. In other words, Locke leveraged an essentially Aristotelian approach to show that Plato’s philosopher king has no clothes—no special dominion over knowledge nor, consequently, over men. He thereby gave “government of, by, and for the people” philosophic roots that enabled America’s founders to establish the first nation in history based on the principle of individual rights.

Thus, although he died seventy-two years before the Revolutionary War, Locke was indispensable in laying the foundation for the American Revolution. Indeed, he was, in a fundamental sense, an American founder.

And look at the flourishing that Locke helped unleash. Since his day, life expectancy and quality of life have risen dramatically while infant mortality has dropped precipitously.[55] The scientists, doctors, and pharmaceutical companies whose outstanding achievements have made this possible could not have done so without the freedom that Locke helped bring about.

We work fewer hours today than people of even a few generations back, yet our work is vastly more productive thanks to the technological advances of brilliant scientists and the astounding ingenuity of entrepreneurs—who have been free to innovate largely because of the impact of Locke’s ideas.[56]

We have greater mobility than anyone in history; we can drive or summon a stranger to bring us wherever we’d like, take a train to work or across the country, hop a flight for a weekend getaway—all with astounding levels of safety.[57] We have more leisure time than any people in history and more options for how to use it.[58] Without the freedom that Locke’s ideas helped bring about, none of these incredible values would have been possible.

When Locke applied the scientific mind-set to questions about government and formed the idea of political freedom based on individual rights, he released a wellspring of human flourishing. To borrow Neil Armstrong’s sentiment, he took one giant leap for mankind.

A Foothold against Liberalism

Yet, despite the extraordinary, life-serving advances they have made possible, Locke’s ideas—and those of the Enlightenment more generally—have been under attack since their inception and still are under attack today.

And virtually every criticism of Lockean liberalism derives from one fundamental problem.

Consider Locke’s “law of nature,” which he says is “the command of the divine will, knowable by the light of nature.”[59] Although it supposedly comes from God, we discover it by reason, and it leads us to understand that all men ought to be equally free. But Locke doesn’t say how we discover it, nor do his followers. Jefferson, for instance, held that, if not the law itself, then at least its effects—our rights—are “self-evident.”[60] However, many people have disagreed that they are self-evident and even have ridiculed the idea. As philosopher Alasdair MacIntyre put it, “there are no such rights, and belief in them is one with belief in witches and unicorns.”[61] Without a clear, reasoned explanation, both Locke’s “law of nature” and its implications for our conduct are open to interpretation—or outright rejection.

Berkeley, for instance, argued that the “law of nature” demands that citizens practice absolute blind obedience to their rulers—even if those rulers clearly are in the wrong. In his book Passive Obedience—published just eight years after Locke’s death—he wrote, “loyalty is a natural or moral Duty; and Disloyalty or Rebellion in the most strict and proper Sense, a Vice or Breach of the Law of Nature.” And, Berkeley added, if men (such as Locke) fail to see this “law of nature” for themselves, perhaps it’s because they’ve been imbued since childhood with immoral customs.[62] In any case, Berkeley held, such men morally must comply.

Likewise, Kant—despite some superficial paeans to political freedom and limited government—insisted that we owe our leaders blind obedience. In his essay “Perpetual Peace,” Kant asks, “Is rebellion a rightful means for a people to use in order to overthrow the oppressive power of a so-called tyrant . . . ?” He answers:

The rights of the people have been violated, and there can be no doubt that the tyrant would not be receiving unjust treatment if dethroned. Nevertheless, it is in the highest degree wrong if the subjects pursue their rights in this way, and they cannot in the least complain of injustice if they are defeated in the ensuing conflict and subsequently have to endure the most severe penalties.[63]

Contrary to Locke’s “law of nature” and the right of revolution entailed therein, Kant holds that“it is the duty of the people to tolerate even what is apparently the most intolerable misuse of supreme power.”[64]

American “Progressives” later repudiated the very possibility of Lockean God-given, “natural,” or “inherent” rights, on the grounds that such rights contradict evolutionary science. In a 1916 speech, Frank Johnson Goodnow said that the “conception of private rights as inherent and not based upon [man-made] law” came about “because it has been believed that the individual has rights with which he has been endowed by his Creator.” But, he continued, in the light of newly discovered science, this makes no sense. “The political philosophy of the eighteenth century was formulated before the announcement and acceptance of the theory of evolutionary development,” which revealed that the individual “is primarily a member of society and that only as he recognizes his duties as a member of society can he secure the greatest opportunities as an individual.”[65] In other words, science cut the ground out from under religion, obliterated the theory of God-given “natural” rights, and left the individual at the mercy of the collective.

In 1935, another Progressive spokesman, John Dewey, further clarified the demise of such rights. Referencing Jeremy Bentham (who famously said that natural rights are “nonsense upon stilts”) and David Hume (who denied the possibility of deriving any moral principles via reason), Dewey mocked the idea of natural rights and liberties. Modern liberals realize that “Natural rights and natural liberties exist only in the kingdom of mythological social zoology,” he jeered.[66] “The ideas of Locke embodied in the Declaration of Independence were congenial to our pioneer conditions,” but they’re outdated now, and liberals need to reverse course. “Organized social planning,” he concluded, “is now the sole method of social action by which liberalism can realize its professed aims.”[67]

Thus, Dewey and his fellow Progressives helped to create a chasm between what (for the sake of clarity) we now call “classical liberalism”—a system of ideas developed to support liberty—and what has come to be called “modern liberalism” or “Progressivism,” a system of ideas developed to replace liberty with all manner of government interference in the lives of individuals.

Because Locke’s conception of rights and, by extension, the American Founders’ conception, ultimately was based on God—and because no one could prove the existence of God, much less rights that emanate from him—classical liberalism and the freedom it championed could not endure.[68]

If we want to secure a future of freedom and flourishing—if we want to advance the Enlightenment and live in it today—we must progress beyond the theory of God-given natural rights. We must come to understand the secular source and nature of rights, and we must be able to explain clearly and on fully rational grounds what rights are, where they come from, and how we know it. To my knowledge, the only thinker to provide such a basis for rights was Ayn Rand.[69]

Locke’s Legacy

None of this is to denigrate John Locke. The fact that we can see and address these problems is a testament to his achievements. We couldn’t begin to discuss such issues if we lived in North Korea or Iran—countries largely based on ideas Locke spent much of his life refuting. We can work to fix the foundation of free society only because of the relative freedom we still enjoy—freedom made possible by Locke and his followers.

Isaac Newton once reflected, “If I have seen further, it is by standing on the shoulders of Giants.” Those who built America—the freest and most moral country on earth—stood on the shoulders of John Locke.

We who fight for individual rights and freedom today stand on his shoulders, too.



[1]. For example, see Arthur Hermann, The Cave and the Light: Plato Versus Aristotle, and the Struggle for the Soul of Western Civilization (New York: Random House, 2013). [2]. Thomas Jefferson, Writings (New York: Literary Classics of the United States, 1984), 1501. [3]. Jefferson also credited Aristotle, Cicero, and Algernon Sidney with helping to shape the American mind. See Jefferson, Writings, 1501. Nonetheless, Jefferson considered Locke (along with Isaac Newton and Francis Bacon) among the “trinity of the three greatest men the world had ever produced,” and he relied heavily on Locke’s Two Treatises in his drafts for the Declaration of Independence. See “Thomas Jefferson to Benjamin Rush, 16 January 1811,” Founders Online, National Archives, [4]. Among Locke’s predecessors arguing for natural rights was Hugo Grotius. Among Locke’s contemporaries arguing for natural rights were Samuel von Pufendorf and Algernon Sidney, the latter of which, like Locke, aimed to refute Robert Filmer. For more on natural rights theories prior to Locke, see Richard Tuck, Natural Rights Theories: Their Origin and Development (Cambridge: Cambridge University Press, 1979). [5]. See Ira Stoll, Samuel Adams: A Life (New York: Free Press, 2008), 99, 102–3. [6]. Hamilton also recommended reading Grotius, Puffendorf, Montesquieu, and Burlemaqui. See Alexander Hamilton, “The Farmer Refuted, &c., February, 23, 1775,” Founders Online, National Archives, [7]. C. Bradley Thompson, John Adams and the Spirit of Liberty (Lawrence: University of Kansas Press, 1998), 61; Adams also compared his task of defending key republican state constitutions against the attacks of French economist Anne Robert Jacques Turgot with Locke’s “labored reasonings” to “show the absurdity of Filmer’s superstitious notions.” See Thompson, John Adams and the Spirit of Liberty, 98. [8]. Thompson, John Adams and the Spirit of Liberty, 11–22; Benjamin Franklin, Writings (New York: Library Company of America, 1987), 1321, 1249, 323–53. [9]. Roger Woolhouse, Locke: A Biography (Cambridge, UK: Cambridge University Press, 2007), 3. [10]. A barometer is a device for measuring atmospheric pressure. A thermoscope is a device for measuring temperature, a precursor to the thermometer. A hygrometer is a device for measuring the amount of humidity and water vapor in the atmosphere, in soil, or in confined spaces. [11]. Woolhouse, Locke, 121. [12]. Woolhouse, Locke, 94–95. [13]. Woolhouse, Locke, 239. [14]. The length of a pendulum whose period was one second was thirty-nine inches. Locke’s “philosophical or universal foot,” as he called it, was one-third of this: thirteen inches. The “philosophical foot” was then divided into ten “inches,” these into ten lines, and the lines into ten grys. Grys being one-thousandth of a philosophical foot, the system enabled very precise and minute measurements. [15]. This journal was the Bibliothèque Universelle et Historique, a French-language journal published in Amsterdam by the French immigrant theologian Jean Le Clerc. In this journal, Locke also published his New Method of a Commonplace Book, an abridgment of his (as yet unpublished) Essay Concerning Human Understanding, and a review of a medical work by Robert Boyle. See J. R. Milton, “Locke’s Publications in the Bibliothèque Universelle et Historique,” British Journal for the History of Philosophy 9, no. 3 (May 25, 2011), [16]. Woolhouse, Locke, 93. [17]. Locke’s friend Pierre Toinard had this published in French under the title Méthode nouvelle de dresser des Recueils, and Locke later got around to publishing it in English as A New Method of Making Common-Place-Books. [18]. Woolhouse, Locke, 4. [19]. Woolhouse, Locke, 314. [20]. Woolhouse, Locke, 248. [21]. John Locke, An Essay Concerning Human Understanding, edited by Kenneth Winkler (Indianapolis: Hackett, 1996), xvi. [22]. Despite Locke’s intention to pursue a life of study and experiment, he depended on several patrons, and he was somewhat obliged to take up tasks they asked of him. He worked as a secretary, ran errands, accompanied dignitaries and students on their travels, served on several government councils and as commissioner for Greenwich Hospital, and even helped plan a wedding. He traveled almost constantly, was always being interrupted, and for the most part had ready access to the mass of books he collected only for short intervals between trips. In fact, he did not have all of his books in one place between 1667 and 1691, the twenty-four years in which he published all of his major works. Locke’s comings and goings led one not-so-generous critic to characterize him as a “traveling tutor” who “fixes nowhere, has no habitation,” but rather “creep[s] into houses, and insinuat[es] into families.” See Woolhouse, Locke, 399. [23]. See Andrew Bernstein, “Aristotle Versus Religion,” The Objective Standard 9, no. 1 (Spring 2014), [24]. Woolhouse, Locke, 65. [25]. Woolhouse, Locke, 108. [26]. Peter Anstey, John Locke and Natural Philosophy (Oxford: Oxford University Press, 2011), 97–103. [27]. Woolhouse, Locke, 94–95. [28]. Locke, An Essay Concerning Human Understanding, 4–5. [29]. René Descartes, Meditations on First Philosophy (Cambridge: Cambridge University Press, 1996), 27. [30]. René Descartes to Guillaume Gibieuf, January, 19, 1642, quoted in Kurt Smith, “Descartes’ Theory of Ideas,” Stanford Encyclopedia of Philosophy, June 14, 2017, [31]. Descartes, Meditations on First Philosophy, 12. [32]. Locke, An Essay Concerning Human Understanding, 5–6. [33]. John Locke, The Works of John Locke in Nine Volumes, vol. II (London: C. Baldwin, 1824), loc. 4052–53, available at [34]. Nicholas Stang, “Kant’s Transcendental Idealism,” Stanford Encyclopedia of Philosophy, March 4, 2016, [35]. Thankfully, Locke’s Tracts weren’t published until 1967. [36]. Alexander Moseley, “John Locke: Political Philosophy,” Internet Encyclopedia of Philosophy, (accessed July 25, 2019). [37]. The same goes for his Two Treatises of Government, also published anonymously—and only a decade after Locke drafted it. [38]. John Locke, Two Treatises of Government and A Letter Concerning Toleration (Overland Park, KS: Neeland Media, 2009), 153. [39]. Locke, Two Treatises, 162. [40]. Locke, Two Treatises, 152. [41]. Locke, Two Treatises, 159. [42]. Jefferson, Writings, 285. [43]. Thomas Hobbes, Leviathan, quoted in W. T. Jones, A History of Western Philosophy: Hobbes to Hume (San Diego, CA: Harcourt Brace Jovanovich, 1952), 146. [44]. Heraclitus, “Heraclitus of Ephesus,” Readings in Ancient Greek Philosophy, 4th ed., edited by S. Marc Cohen, Patricia Curd, and C. D. C. Reeve (Indianapolis: Hackett, 2011), 35. [45]. Hobbes also held that men are endowed with a rational faculty. But instead of it leading men to develop civil society, it leads them first to pillage and plunder and, only after experiencing the consequences of this, to submit to the most powerful tyrant; Locke, Two Treatises, 89. [46]. Locke, Two Treatises, 79, 87. [47]. Locke, Two Treatises, 79–80. [48]. Locke, Two Treatises, 97–98. [49]. Locke, Two Treatises, 142. [50]. Locke, Two Treatises, 75. [51]. For more on the futility of anarchy, see Craig Biddle, “Libertarianism vs. Radical Capitalism,” The Objective Standard 8, no. 4 (Winter 2013), [52]. Locke, Two Treatises, 97–98. [53]. Locke, Two Treatises, 136–38. [54]. I’d like to thank Andrew Bernstein for reminding me of this point. [55]. According to Oxford economist Max Roser, today “No country in the world has a lower life expectancy than the countries with the highest life expectancy in 1800.” See Max Roser, “Life Expectancy,” Our World in Data, (accessed July 25, 2019). [56]. Max Roser, “Working Hours,” Our World in Data, (accessed July 25, 2019). [57]. “The New Automobility: Lyft, Uber and the Future of American Cities,” Schaller Consulting, July 25, 2018,; Timothy Sandefur, “Flying Is Safer Than Eating,” The Objective Standard 14, no. 2 (Summer 2019), [58]. Kristie Engemann and Michael T. Owyang, “Working Hard or Hardly Working? The Evolution of Leisure in the United States,” Federal Reserve Bank of St. Louis, January 1, 2007,; James Sherk, “Upwards Leisure Mobility: Americans Work Less and Have More Leisure Time than Ever Before,” Heritage Foundation, August 31, 2007, [59]. John Locke, Questions Concerning the Law of Nature, 2nd ed. (Ithaca, NY: Cornell University Press, 2008), 101. [60]. Of course, neither rights nor their cause(s) are self-evident. Gravity is a law of nature—the effects of which are self-evident. Drop a book, and you’ll see it tumble to the ground. The evidence for rights, by contrast, is not immediately available to the senses but instead requires an abstract process of thought that integrates a massive number of observations. For an explanation of the source and secular nature of rights, see Ayn Rand, “Man’s Rights,” The Virtue of Selfishness: A New Concept of Egoism (New York: Signet, 1964). [61]. Quoted in Craig Biddle, “Ayn Rand’s Theory of Rights: The Moral Foundation of a Free Society,” The Objective Standard 6, no. 3 (Fall 2011), [62]. George Berkeley, Passive Obedience: or, the Christian Doctrine of Not Resisting the Supreme Power, Proved and Vindicated (London: 1712), 4, [63]. Immanuel Kant, The Political Writings of Immanuel Kant, edited by Hans Reiss, translated by H. B. Nisbet (Cambridge: Cambridge University Press, 1970), 126. [64]. Kant, Political Writings of Immanuel Kant, 145. [65]. Frank Johnson Goodnow, “The American Conception of Liberty,” in American Progressivism: A Reader, edited by Ronald J. Pestritto and William J. Atto (New York: Lexington Books, 2008), 61–62. [66]. Jeremy Bentham is here quoted from Biddle, “Libertarianism vs. Radical Capitalism.” Regarding Hume’s claim that moral principles cannot be derived via reason, and Ayn Rand’s demonstration to the contrary, see Craig Biddle’s Loving Life: The Morality of Self-Interest and the Facts that Support It(Richmond, VA: Glen Allen Press, 2002), chapters two and three. [67]. John Dewey, Liberalism and Social Action (New York: G. P. Putnam’s Sons, 1935), available at [68]. In an essay titled “The Ground of Locke’s Law of Nature,” Thomas West pulls together passages concerning Locke’s “law of nature” scattered throughout his works and concludes, “Locke’s reasoning on the law of nature leads us to conclude that he has a far richer understanding of the limits of reason, and the importance of nonrational features of society such as religion and customs, than he is generally credited with.” See Thomas West, “The Ground of Locke’s Law of Nature,” Natural Rights, Individualism, and Progressivism in American Political Philosophy (Cambridge: Cambridge University Press, 2012). Locke’s appeals to God also undermine his argument for property rights. See Fred D. Miller and Adam Mossoff, “Ayn Rand’s Theory of Rights,” Foundations of a Free Society: Reflections on Ayn Rand’s Political Philosophy, edited by Gregory Salmieri and Robert Mayhew (Pittsburgh: University of Pittsburgh Press, 2019), 132. [69]. See Ayn Rand, “Man’s Rights”; see also Craig Biddle, “Ayn Rand’s Theory of Rights: The Moral Foundation of a Free Society”; see also Carl Barney and Craig Biddle, “Liberty: What Is It? Why Is It Good? On What Does It Depend?,” The Objective Standard 14, no. 1 (Spring 2019),

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