John Locke was born on 29 August 1632 in Wrington, Somerset. He died on 28 October 1704 in the home of Damaris Masham in High Laver, Essex, as she read to him from the Bible. He was the eldest child of John Locke, a lawyer and clerk to the Justices of the Peace, and his wife, Agnes, both of whom were of Puritan stock, a factor which weighed with them when in 1642 England became divided by civil war. At the outbreak of war, John Locke senior became a captain in the Parliamentary Army, under Colonel Popham, MP for Bath. He held this position for about a year, until the Royalists captured Somerset for the King, when he returned to civilian life. At the end of the war, through the intervention of Popham, John Locke junior obtained a place at Westminster School, then the outstanding school in the country. It was close by, in January 1649, that Charles I was executed. In the following years Locke did well enough academically to obtain a scholarship to Christ Church, Oxford, which he entered in 1652 at the age of twenty. He graduated BA in 1656 and MA in 1658. It was in the period between these last two events that Locke seems first to have become seriously engaged in those studies that were to become lifelong commitments. In particular these included medicine, philosophy in its widest sense, and political theory. His involvement in medicine was undoubtedly aided by his contact with members of the Oxford Experimental Philosophy Club, which included John Wilkins, William Petty, Christopher Wren, Robert Hooke and, above all, Robert Boyle. Soon Locke was engaged in research with Boyle on the nature of human blood, experimental work which arose from Harvey’s discovery earlier in the century of the circulatory function of the heart, which revolutionized medical theory. Locke’s interest in philosophy was stimulated by reading Descartes, an event which was to be of central importance to him, for it was Descartes’s clear and powerful system which stimulated within him a highly constructive reaction which was finally to emerge nearly thirty years later as his mature philosophical position.
Locke’s earliest important philosophical thoughts emerged in his essays on the law of nature, which were probably given as lectures in his role as Censor of Moral Philosophy at Christ Church in 1663–4. In these he argued both for such a law of nature but also that the law could be known only by the combination of reason and sense experience. It was not knowledge innately inscribed on our minds but had to be discovered by the proper use of our faculties.
Locke’s duties as tutor did not prevent him continuing his medical and scientific research. When Anthony Ashley Cooper (1621–83), a leading political figure of the age and later the first Earl of Shaftesbury, met Locke on a visit to Oxford and subsequently invited him to join his London household, it was partly to act as physician to the family. Locke accepted the invitation and moved to Exeter House in the Strand in 1667. He was never to live in Oxford for long periods again. In London he was soon elected a Fellow of the now blossoming Royal Society and engaged in medical research with the greatest physician of the age, Thomas Sydenham, as well as continuing to work with Boyle.
Locke’s place in the Shaftesbury household brought him into direct contact with the great political issues of the day. Of these none was more important than the question of religious toleration. It was on this topic that Locke drafted some early views, probably for Shaftesbury’s benefit. In his search for an intellectual foundation for the views to which he was committed it is quite possible that Locke, with a group of friends, was led to explore the epistemological questions that lie at the base of the religious and moral issues surrounding toleration. The draft paper that he produced in 1671 was eventually to become the Essay concerning Human Understanding. In the meantime he travelled widely in France, spending much time at the medical school in Montpelier and absorbing much of contemporary French thought, especially, though not only, from his Protestant medical friends. He returned at Shaftesbury’s behest in 1679 just as the latter was achieving his highest position of power and as the great debate over the ‘Exclusion Crisis’ – the possibility of excluding the King’s Catholic brother from the succession – became a central issue.
It was soon after this – the precise date is disputed – that Locke drafted Two Treatises of Government, though it was not to be published until 1690. It therefore may in some part be seen as an ‘Exclusion Tract’ rather than the justification for the Revolution of 1688 which it purported to be. Its argument, however, may be used in both contexts.
Shaftesbury’s fortune was not sustained. His struggle against the Stuarts was going badly and in 1682 he escaped to Holland, where he was to die the following February. It was a severe blow to Locke, who had become closely identified with Shaftesbury’s political causes, and in the autumn of 1683 he too took ship for Holland, where he was to remain until 1689. Meanwhile Locke had in 1682 become acquainted with Damaris Cudworth, daughter of the philosopher Ralph Cudworth and a philosopher in her own right. It was a friendship which on both sides might easily have become something much stronger. Locke became closer to her than to any other human being, though her marriage while he was in Holland almost certainly precluded any closer relationship than deep friendship.
Although in Holland Locke was never far away from the radical British exiles planning Monmouth’s abortive rebellion and ultimately William’s invasion of 1688, his major achievement while there was the completion of the Essay concerning Human Understanding. He returned to England in 1689 and his two great works, together with the earlier Epistola de tolerantia, were published within the year.
Locke’s remaining years were spent in public service when his health allowed, in revising and adding to his publications and in replying to his critics, of whom the most important was Edward Stillingfleet, Bishop of Worcester. With his friend Isaac Newton, Locke began to acquire the position of one of the twin founding fathers of the new philosophy that has become known as the Enlightenment.
Locke’s philosophy, while deeply indebted to the new direction given by Descartes, also followed in an empiricist tradition already in place which was powerfully present in Francis Bacon, Thomas Hobbes, Pierre Gassendi, and indeed in earlier thinkers going back to classical Greek sources. Locke’s distinctive contribution was to provide a deeper and more complete justification for that empiricism than had any of those earlier thinkers; and in a form that meshed with the rising empirical method associated with the growth of the natural sciences, as exemplified in the work and philosophy of the Royal Society. The Essay concerning Human Understanding (1690) is written in four books preceded by an ‘Epistle to the Reader’ in which Locke describes himself as an under-labourer ‘clearing ground a little, and removing some of the rubbish, that lies in the way to knowledge’. The ‘master builders’ were such as Boyle and Newton, i.e. the natural scientists of the modern age. The more humble task of the philosopher was to map out the nature and limits of human understanding to discover what it is that mind is and is not capable of knowing. In thus redefining the role of the philosopher Locke set the agenda, at least in the area now known as analytic philosophy, for the next three hundred years. He followed Descartes in making ideas central to his account. What exactly ideas are for Locke remains an important and contentious issue in the exegesis of his philosophy.
The first book of the Essay is a sustained assault on the claim that there are ideas innate in the mind from its first creation. Such innate ideas had been assumed or argued for by philosophers from at least Plato onwards to account for our knowledge, especially in areas such as religion or morals. Against this Locke provided several objections. First, he pointed out that the argument from universal consent did not in itself establish innateness as long as there was an alternative plausible explanation for the agreement. Furthermore, there was no such universal consent among men. It is absurd to say that children know things which they plainly do not understand, such as the laws of logic. For other supposed examples there was plenty of empirical evidence – Locke drew on his wide reading in travel books – to show that many people did not have the idea of God or a common understanding of moral truths. If we say that any principle is innate to which we assent as soon as we understand it then, for example, all of mathematics is innate, which nobody wishes to maintain. The truth is that we can only recall those things which we have already experienced and ideas cannot be said to be in the mind until we are conscious of them. To say there are ideas in the mind of which we have never been conscious amounts to a contradiction.
In Book II Locke gives his own answer to the question about the origin of ideas. They are all, he says, the product of experience. It is this claim that is the heart of his empiricism. The mind, he says, should be supposed to be as ‘white paper, void of all characters, without any ideas’. Ideas themselves have two sources: sensation, where the ideas come to us from one of the five senses; and reflection, where the ideas originate from the activity of the mind itself, such as our awareness of our perceiving, believing, doubting, willing, etc. Locke is careful not to identify the mind with thinking, which he takes to be a mistake made by Descartes. For the mind continues to exist even in deep sleep when it cannot be said to be aware of any ideas at all.
In his account of ideas Locke distinguishes between simple and complex. Simple ideas are the atoms of experience – the coldness and hardness of a piece of ice, the smell and whiteness of a lily, the taste of sugar. A special property of simple ideas is that we cannot invent new ones. If we have never experienced the idea of ‘red’ then we cannot conjure it up for ourselves. Some simple ideas come to us only by one sense: colour by vision, sounds by our ears, and so on. Others, such as figure and motion, come from more than one: we can see and feel that an object is moving or is square. Complex ideas are aggregations of simple ideas. Most are directly the product of experience – we see or remember from having previously seen, say, the oak tree or the horse – but we can also invent new ones that we have never experienced, such as that of the dragon.
From his thoughts about the nature of simple ideas Locke develops his account of a distinction between two kinds of ideas and their corresponding properties, which has figured largely in the discussion of his philosophy: the famous distinction between the primary and secondary qualities of objects and their corresponding ideas. In formulating his position Locke drew on a distinction that was already well established and went back to the Greek atomists such as Epicurus. More recently it had featured in the work of Galileo, Descartes, Gassendi, Boyle and many other contemporary thinkers, but it is Locke’s discussion that has tended to dominate the modern literature, even though he probably saw himself as only clarifying an already widely accepted distinction. For all of those who subscribed to it, the division of properties into primary and secondary was closely connected with their subscribing also to an atomist or corpuscular account of matter. If the fundamental particles of matter were tiny atoms then there was need of an account of their basic properties and the relationship between them and the apparent properties of gross bodies. Locke’s answer was that material objects have two kinds of properties: fundamental ones such as size and shape, and, secondly, dispositional powers. The basic properties caused in the observer a corresponding idea in which the idea resembled its cause in the object. Our idea of the snowball as round, say, resembles the roundness of the snowball itself. In the case of the idea of whiteness which the snowball causes in us, however, there is no such resemblance. All there is in the snowball are the shape, solidity and resulting texture of the object which has the power to generate within us the idea of whiteness. Although Locke thinks there are good empirical arguments for accepting the distinction, there can be no doubt that its plausibility does depend heavily on the acceptance on other grounds of an atomist or corpuscularian theory of matter. In that sense it was deeply connected with a rejection of the Aristotelian account of properties in terms of matter and form, and which was such a prominent feature of the seventeenth-century scientific revolution.
Along with the primary and secondary quality distinction, Locke also rejected in a powerful and positive way the Scholastic commitment to real and nominal essences. According to the Scholastics, science required the identification of the real essences of the natural species of objects, whether animal, vegetable or mineral. Locke, from his empirical principles, argued that we can never be sure that we have identified the essential properties of any natural object. All we can do is assemble provisional identifications – nominal essences – which in the light of further investigation may have to be revised. In all our dealings with the physical world our supposed discoveries of universal truths – what were just beginning to be called laws of nature – could never be other than probabilities which might have to be revised in the light of further observation. It was through such reflection that Locke was led to argue that the limits of human knowledge were much narrower than was generally supposed. Knowledge was certainty. But the natural sciences could rarely achieve anything more than probabilities and to claim or aspire to more was contrary to a fundamental truth about the human condition. To deny it would only lead to dogmatic claims that could not be defended.
There were, however, other important areas in which knowledge was possible. We can know of our own existence and other intuitively certain truths, such as that white is not black. And by demonstration we may know such things as that the three angles of a triangle are equal to two right angles. We can similarly demonstrate that there must be an intelligent first cause of all that there is, that is, that it is possible to prove demonstratively the existence of God. Moral knowledge, too, is possible, in a way similar to mathematical knowledge. Aside from these areas, however, there was always scope for doubt. It was therefore very important that such limitations on our knowledge be recognized, for they have important implications for how we should live. For where we cannot be certain we have no right to impose our views on others.
The political implications of Locke’s epistemology were not spelt out in the Essay and we have to turn to his other writings to identify them. Indeed, the connection between the two sides of Locke’s philosophy is so little set out by him that many have failed to see it. It is, however, a major feature of his thought, for much of his argument for religious toleration, especially in the Epistola de tolerantia but also elsewhere, rests on the epistemological point that many religious claims can never be classified as other than opinion. Locke was committed to the view that we can certainly know enough of God and morality to obtain salvation. But many religious claims went well beyond this and assent to them could not be required from those who in conscience could not accept them.
The Essay contains many other important and influential discussions. One is Locke’s account of personal identity. What is it that makes person A at time t identical with person B at time t’? Locke provides a careful analysis of the conditions which have to be met for different kinds of object to count as the same over time. Organic things have to participate in the same life. This way an oak tree, for example, can be the same tree, even though at one time it was tiny and is now large. It is similar with the biological concept of a man, says Locke. But a person is something different. The crucial continuity is supplied here, he argues, by memory, which supplies continuity of consciousness. Continuity of consciousness can in principle transcend bodily identity, which is only contingently related to the concept of ‘same person’. Although there are major problems with Locke’s account – memory presupposes identity and does not constitute it – his discussion, although not the first in modern times, was by far the most powerful and has largely set the agenda for subsequent consideration of the issues.
A major problem is often thought to lie at the heart of Locke’s epistemology which is fatal to his empiricist programme. Locke seems to be claiming that all we are ever aware of are ideas, though in normal conditions these ideas are often produced by a complex causal interaction between our mind and physical objects in the world. But if we are only ever aware of ideas at the end of this causal chain how can we ever know that there is an independent physical world at all? To this objection there are several possible responses. One important one is to note that this way of setting up the problem presupposes that ideas are to be understood as some kind of things which somehow interpose themselves between the mind and the physical world – the external world, as it is often called. But it is far from clear that ideas are for Locke such substantial entities. To have an idea is certainly to have an experience of some kind. But the experience may itself be of a physical object. It is far from clear that Locke’s language commits him irrevocably to a ‘veil of perception’ doctrine. And it is worth emphasizing that he counts as one of our few kinds of knowledge the particular existence of objects that we can directly see in front of us – the desk at which I currently sit, for example. Although Locke’s empiricist descendants such as Berkeley and Hume do seem to regard ideas in ways which have the consequences outlined (as they appreciated), it is far from clear that Locke’s position is open to such simple refutation.
The impact of Locke’s Essay is difficult to overstate. Not only was it widely read (and mis-read) by philosophers both immediately and for at least the next hundred years, it also had an enormous impact on virtually every other branch of intellectual inquiry from theology to psychology and all the natural sciences. In France it was used to support a new materialism that, while never part of Locke’s intentions, nevertheless added much force to secular thinking throughout the eighteenth century. Furthermore, and perhaps most importantly, Locke’s style of philosophizing laid the groundwork for the problems that were to dominate intellectual inquiry and the method in which they were to be met in a way which is very much still with us.
Locke’s political philosophy, as we have it in the Two Treatises of Government (1690), is a founding document of the modern liberal democratic state. Although, as we have seen, Locke connected the text directly with the ‘Glorious Revolution’ of 1688, its most important message is one about the perennial relationship between individuals and government. Locke argues, contrary to Robert Filmer and other divine-right theorists, that no person has a natural right to rule over others. The individual was naturally in a perfect state of freedom. But this was not, he said, the same as a state of licence, for every person was subject to the natural law, the law of reason, which places precise limits on our behaviour. The problem with the state of nature so understood was that, although men had rights to life, liberty and property in such a state, they could not always enjoy those rights because others, for their own ends, would often violate them. Accordingly, men would gather together and enter into a contract to protect their natural rights by placing authority to enforce the natural law in the hands of an executive power, such as a monarch. The function of the state, then, is to provide the conditions under which citizens may enjoy their natural rights. It does so by providing external protection against other states and by guaranteeing internal order. If the state fails to provide such conditions, or itself violates the natural rights of its citizens, then the people are justified in removing the ruler, by force if necessary. Revolution, in other words, is sometimes justified. In those areas where no such infringements will occur then the will of the majority should prevail.
A central part of Locke’s analysis turns on the way in which property may be legitimately acquired. At the outset, Locke says, all is held in common. Men, through work, can turn what was of little or no value into something productive – for example, the virgin soil into crops or herds. Thus the individual acquires a property right in the thing created. And it is the labour of the individual concerned that generates that value. Property rights can therefore be generated in the state of nature. The reason for entering into civil society by means of the contract is because it is only through the creation of the central power that the individual can hope to keep what is rightly his by labour.
It is not only property rights that the state should protect (though Locke sometimes writes as if all rights were property rights – those against violence, for example, arise because we have a propriety in our own bodies). But the young child has rights against the parent and the servant against the master (and in the latter case, vice versa). And we all have a right to expect others to carry out their side of the contracts into which they have freely entered. Once again it is difficult to overstate the influence of Locke’s analysis. In placing the central function of the state as that of the guardian of individual natural rights and advocating majority decision in areas where natural rights are not in question Locke set the framework for those major revolutions of the eighteenth century which saw the overthrow of absolute monarchy and the first modern democratic societies. Exactly what place in the actual political events Locke’s texts played is problematic but there can be no doubting the direction in which they pointed and the appeal of his argument.
Locke’s influence was not confined to his major work. His writings on education, theology and economics also made a considerable impact right through until at least well into the nineteenth century. His posthumous works were published by the son of a cousin, Peter King.