John Locke (26 August 1632 – 28 October 1704) was a British philosopher, writer, political activist, medical researcher, Oxford academic, and government official. Locke was a champion of empiricism, arguing that all knowledge was derived from experience. Among his most notable works is An Essay Concerning Human Understanding, which provides a defence of empiricism and the origins of ideas and understanding. In this work, Locke rejects the idea of innate principles, and argues that all knowledge comes from experience. Locke also wrote on religious toleration and social contract theory. He opposed authoritarianism and argued that individuals should use reason to discover the truth.
Locke was born into an English Puritan family of modest means, but was able to obtain an excellent education by way of his father's connections. 1 In 1647, at the age of fifteen, he began studies at Westminster School, considered London's best. At twenty, he began studies at Christ Church College, Oxford. His studies focused on logic, metaphysics, and languages taught within the framework of Aristotelian scholasticism, for which he developed an intense dislike. 23 This was more than a century after Nicholas Copernicus (1473-1543) had posited his heliocentric cosmology in 1543, and forty years after Galileo Galilei (1564-1642) published his observations with the telescope in 1610. These developments had cast Aristotelianism into doubt. 4 Like many ambitious students of the time, Locke sought alternative resources outside the formal curriculum, and such resources were abundant at Oxford. He became involved with a discussion group organized by John Wilkins (1614-1672)and was exposed to the experimental philosophy and the ideas of Francis Bacon (1561-1626) who argued for an inductive methodology for science. The Wilkins group was the nucleus of what would later become the 'Royal Society of London for Improving Natural Knowledge', known simply as the Royal Society. The Royal Society became a formal institution in the 1660's and England's main society for the promotion of natural philosophy. The society would set itself in opposition to the Aristotelian scholasticism of the universities, advocating the study of nature rather than of ancient texts. 2 Locke's notebooks indicate a strong interest in medicine and chemistry. He attended the lectures of the great anatomist Thomas Willis (1621-1675) and took careful notes. 56
After Locke received his bachelor's degree in 1656, he remained at Oxford to study medicine. He worked closely with Dr. Thomas Sydenham (1624-1689), renown for his pioneering work in the treatment of infectious diseases. 1 Robert Boyle (1627-1691) succeeded John Wilkins as the leader of the scientific group at Oxford, and became Locke's scientific tutor. Boyle ascribed to the corpuscular mechanistic philosophy associated with Rene Descartes (1596-1650), and was noted for his physical experiments. The corpuscular philosophy held that the visible properties of the natural world were due to interactions between invisibly small particles or corpuscles. Locke read Boyle's and Descartes works, as well as those of Pierre Gassendi (1592-1655), who emphasized the role of the senses in knowledge. He learned from his experimentalist associates and from the writings of Gassendi, to be skeptical of Descartes' rationalism. 217 He accepted Descartes' corpuscular view of matter, his dualistic view that mind and matter were separate substances, and believed the world to contain genuine causal interactions between physical objects. 5
Locke became personal physician to Anthony Ashley Cooper (1621-1683) (Lord Ashley), a leading English political figure during the 1670's and 1680's. 1 He was an early member of the Royal Society and knew most of the major English natural philosophers, including Isaac Newton (1643-1727) and some continental ones as well. This community was concerned with arguing for the reliability of observation and experiment as a means of acquiring knowledge as opposed to Aristotelian intuition or Cartesian rationalism. 2 Locke's most important contribution to this argument was his An Essay Concerning Human Understanding, published in 1689. Locke and Newton became directly acquainted while Locke was finishing this work. When Locke read Newton's Philosophiae Naturalis Principia Mathematica, published in 1687, he found epistemological views similar to his own. Both had absorbed the views current in the Royal Society. Locke's essay received its warmest reception from the members of the society, and can be deemed an expression of their collective understanding of scientific methodology. 5
In the first book of his Essay Concerning Human Understanding Locke begins by arguing that there are no principles or ideas that are innate in the human mind. In seventeenth century England, such principles were widely held to exist and to be necessary to the stability of religion and morality. 2 "Nothing is more commonly taken for granted" he wrote, "than that certain principles both speculative and practical are accepted by all mankind. Some people have argued that because these principles are (they think) universally accepted, they must have been stamped into the souls of men from the outset." 8 He denies that we hold such innate principles, including innate ideas of God, identity, or impossibility. This criticism was aimed widely, but was directed, in part, at Cartesians, who held, among other things, that we have an innate idea of substance. 5 Locke maintained that if there were such innate principles, they would be known to everyone, even "children, idiots, savages, and illiterate people", which was clearly not the case. 8 Mathematical truths likewise cannot be innate, as these must be discovered by reason. 2
In the second book, Locke begins his positive account of how people acquire knowledge. "Let us suppose", he writes, "the mind to have no ideas in it, to be like white paper with nothing written on it. How then does it come to be written on?...To this I answer, in one word, from experience". Locke's belief that all knowledge comes from sense experience is empiricism.9 Unlike Descartes, Locke does not seriously entertain the possibility that his senses are fundamentally unreliable. He writes that, "We certainly find that pleasure or pain follows upon the application to us of certain objects whose existence we perceive (or dream we perceive!) through our senses; and this certainly is as great as we need for practical purposes, which are the only purposes we ought to have". 10 When our senses are applied to particular perceptible objects, they convey into the mind perceptions of those things. This sensation is the source of most of our ideas. We can also perceive the workings of our own mind within us, which gives us ideas of the mind's own operations such as "perception, thinking, doubting, believing, reasoning, knowing, willing, and all the different things our minds do", a process which Locke calls reflection. 9 Simple ideas produced by these processes can be grouped into complex ideas, such as those of substances and modes. Substances are independently existing things like God, angels, humans, animals, plants, and constructed things. Modes are dependently existing things like mathematical and moral ideas, which form the content of religion, politics, and culture. Note that while Locke does not believe that we are born with ideas, he believes we are born with faculties to receive and manipulate them. 2 Locke rejected Descartes contention that thinking was an inherent property of the mind. He wrote that "To ask, at what time a Man has first any ideas, is to ask, when he begins to perceive; having ideas, and perception being the same thing. I know it is an opinion, that the soul always thinks, and that it has the actual perception of ideas in itself constantly, as long as it exists; and that actual thinking is as inseparable from the soul, as actual extension is from the body; which if true, to enquire after the beginning of a man's ideas, is the same, as to enquire after the beginning of his soul". 5
As a corpuscularist, Locke took all observable bodies to be composed of invisibly small material particles called corpuscles. Such particles interacted primarily by direct physical contact, which could convey motion. Locke however, did accept Issac Newton's concept of gravitation, believing this attraction at a distance to be a special property added to matter by God. 11 Material bodies had certain primary qualities including size, shape, texture, and motion, which were impossible to separate from them. They also had secondary qualities, which were the object's abilities to produce sensations of color, sound, taste, and smell in human beings when they interact with bodies or particles with the appropriate primary qualities. 11 Unlike Descartes, Locke allowed that it was possible that the soul might be material. In book IV of his Essay, he wrote that "anyone who will allow himself to think freely...will hardly find reason directing him firmly for or against the soul's materiality". He argued that the materiality of the soul was consistent with "the great ends of religion and morality", since God might effect the material resurrection of the dead on Judgment Day. 9
Locke on Scientific Methodology
The Aristotelian scholastic approach to knowledge saw scientific knowledge as certain knowledge of necessary truths, with conclusions deduced from premises that were self-evident. Like many others of his times, Locke did not believe that this sort of knowledge was generally possible in natural philosophy, though he continued to hold it as an ideal. He sought to replace such stringent demands with ones more compatible with the new experimental science, such as that practiced by the Royal Society. He took knowledge to be "nothing but the perception of the connection and agreement, or disagreement and incompatibility, of any of our ideas", with our ideas derived ultimately from sensations. 1011 Locke distinguished between two sorts of knowledge, knowledge of nominal essences which are the set of observable qualities we use to classify a thing, and knowledge of real essences which are the causal grounds of a substance's perceivable qualities. It was this latter sort of knowledge that Locke thought was, for the most part, beyond human reach.12
For Locke, knowledge of the real essences of material substances and the necessary connections of these essences to qualities flowing from them was the deepest sort of knowledge one might, in principle, have in natural philosophy. He imagined this to be knowledge of the corpuscles that make up matter and their sizes, shapes, and arrangements. Given such fundamental knowledge, we could deduce the tertiary qualities of substances; their powers to produce certain effects in other substances. Just as a locksmith knows that a particular key opens one lock but not another, we could know that opium produces sleep, and hemlock causes death and the reasons why.1011
But Locke supposed that such knowledge was, for the most part, beyond human faculties because corpuscles are too small to be discerned by human senses. He wrote that "But while we lack senses acute enough to discover the minute particles of bodies and to give us ideas of their fine structure, we must be content to be ignorant of their properties and ways of operation, being assured only of what we can learn from a few experiments. And what we can learn for sure in that way is limited indeed." 106 In making this case about the limits of our knowledge of a corpuscular world, Locke nonetheless felt confident in relying on the corpuscular hypothesis itself "because that’s the theory that is thought to go furthest in intelligibly explaining those qualities of bodies; and I fear that the human understanding hasn’t the power to replace it..." 10 While knowledge of real essences, was, for the most part, inaccessible to humans, Locke imagined that it was not inaccessible to other epistemic agents with different or more acute senses, such as God, the angels, and the inhabitants of other planets. 1110
Locke supposed that human knowledge was limited to what he called sensitive knowledge; knowledge of nominal essences that comes every day within the notice of our senses. 1112 Like Francis Bacon, he maintained that an important part of the methodology of natural philosophy is the construction of natural histories giving systematic accounts of phenomena. Hypotheses played only a minor role in natural philosophy, though he did accept the value of the theories expressed in Newton's Principia. 6 He wrote that "We should not take up any one [hypothesis] too hastily ... till we have very well examined particulars and made several experiments in that thing we would explain by our hypothesis, and see whether it will agree to them all". 5 Like Newton, he supposed that knowledge could be obtained by observation, experiment, and inductive generalization. Locke’s Essay came to be considered the start of British empiricism, with contributions by subsequent Anglophone thinkers including Berkeley, Hume, Mill, Russell and Ayer.13
In some quarters, Locke’s An Essay Concerning Human Understanding was heavily criticized. Gottfried Wilhelm Leibniz (1646-1716) responded, point-by-point, to Locke’s work in a book length rebuttal, New Essays on Human Understanding, which he finished in 1704, but wasn't published until sixty years later. 14 Leibniz rejected Locke's claim that the senses were the ultimate source of all our ideas and that there were no innate ideas. He wrote that "Experience is necessary...if the soul...is to take heed of the ideas that are within us. But how could experience and the senses provide the ideas? Does the soul have windows? Is it similar to writing tablets or wax? Clearly, those who take this view of the soul are treating it as fundamentally corporeal", a possibility that Locke was willing to countenance, but Leibniz found abhorrent. 14
Leibniz rejected Locke's claim that the mind was initially devoid of ideas, like a blank sheet of paper, because this would make new minds identical, but separate, a possibility ruled out by his Principle of the Identity of Indiscernibles.14 Although he allowed that contingent truths might be learned with the assistance of the senses, logically necessary principles, like the truths of pure mathematics, logic, and some areas of metaphysics and ethics could not come from the senses because no number of specific experiences could demonstrate their necessity. 14 Therefore, he concluded that, "the proof of them can only come from inner principles, which are described as innate". 15 To explain why everyone doesn't have access to these innate ideas, he wrote that "It would indeed be wrong to think that we can easily read these eternal laws of reason in the soul...without effort or inquiry; but it is enough that they can be discovered inside us if we give them our attention: the senses provide the prompt, and the results of experiments also serve to corroborate reason, rather as checking procedures in arithmetic help us to avoid errors of calculation in long chains of reasoning". 15 Leibniz's criticisms of Locke touched off a prolonged debate between empiricists, who maintained, with Locke, that all knowledge derives from experience, and rationalists like Leibniz, who maintained that some knowledge is derived by means other than experience, and must therefore be innate. 16
George Berkeley (1685-1753) questioned Locke and Descartes' conception of a corpuscular mechanistic material world. Drawing on Locke's distinction between mind-dependent secondary qualities and mind-independent primary qualities, he questioned whether primary qualities such as size, shape, texture and motion were, indeed, mind-independent. Denying the existence of material substance, Berkeley attributed intersubjective agreement about the perceived world and its apparent stability to the action of God rather than to the properties of invisible material corpuscles. 1718 Berkeley's criticism of corpuscular matter had a strong influence on subsequent thinkers, including David Hume (1711-1776) and Immanuel Kant (1724-1804).
Here are the works of Locke included in the bibliographic records of this encyclopedia:
- Locke (2015): Locke, John. (2015) An Essay Concerning Human Understanding. Early Modern Texts. Retrieved from http://www.earlymoderntexts.com/authors/locke.
- Locke (2015a): Locke, John. (2015) An Essay Concerning Human Understanding. Book I: Innate Notions. Early Modern Texts. Retrieved from http://earlymoderntexts.com/assets/pdfs/locke1690book1.pdf.
- Locke (2015b): Locke, John. (2015) An Essay Concerning Human Understanding. Book II: Ideas. Early Modern Texts. Retrieved from http://earlymoderntexts.com/assets/pdfs/locke1690book2.pdf.
- Locke (2015c): Locke, John. (2015) An Essay Concerning Human Understanding Book III: Words. Early Modern Texts. Retrieved from http://www.earlymoderntexts.com/assets/pdfs/locke1690book3.pdf.
- Locke (2015d): Locke, John. (2015) An Essay Concerning Human Understanding Book IV: Knowledge. Early Modern Texts. Retrieved from http://www.earlymoderntexts.com/assets/pdfs/locke1690book4.pdf.
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- Dunn, John. (2003) Locke: A Very Short Introduction. Oxford University Press.
- Uzgalis, William. (2016) John Locke. In Zalta (Ed.) (2016). Retrieved from http://plato.stanford.edu/entries/locke/.
- Milton, John R. (1994) Locke's Life and Times. In Chappell (Ed.) (1994), 5-25.
- Westfall, Richard. (1980) Never at Rest: A Biography of Issac Newton. Cambridge University Press.
- Rogers, John. (1982) The System of Locke and Newton. In Bechler (1982), 215-238.
- Anstey, Peter. (2011) John Locke and Natural Philosophy. Oxford University Press.
- Fisher, Saul. (2014) Pierre Gassendi. In Zalta (Ed.) (2016). Retrieved from http://plato.stanford.edu/archives/spr2014/entries/gassendi/.
- Locke, John. (2015) An Essay Concerning Human Understanding. Book I: Innate Notions. Early Modern Texts. Retrieved from http://earlymoderntexts.com/assets/pdfs/locke1690book1.pdf.
- Locke, John. (2015) An Essay Concerning Human Understanding. Book II: Ideas. Early Modern Texts. Retrieved from http://earlymoderntexts.com/assets/pdfs/locke1690book2.pdf.
- Locke, John. (2015) An Essay Concerning Human Understanding Book IV: Knowledge. Early Modern Texts. Retrieved from http://www.earlymoderntexts.com/assets/pdfs/locke1690book4.pdf.
- Kochiras, Hylarie. (2014) Locke's Philosophy of Science. Stanford Encyclopedia of Philosophy. Retrieved from https://plato.stanford.edu/entries/locke-philosophy-science/.
- Osler, Margaret. (1970) John Locke and the Changing Ideal of Scientific Knowledge. Journal of the History of Ideas 31 (1), 3-16.
- Chappell, Vere. (Ed.). (1994) The Cambridge Companion to Locke. Cambridge University Press.
- Look, Brandon. (2017) Gottfried Wilhelm Leibniz. In Zalta (Ed.) (2016). Retrieved from https://plato.stanford.edu/archives/sum2017/entries/leibniz/.
- Leibniz, Gottfried Willhelm. (2017) New Essays on Human Understanding Preface and Book I: Innate Notions. Early Modern Texts. Retrieved from http://www.earlymoderntexts.com/authors/leibniz.
- Markie, Peter. (2015) Rationalism vs. Empiricism. In Zalta (Ed.) (2016). Retrieved from http://plato.stanford.edu/archives/sum2015/entries/rationalism-empiricism/.
- Downing, Lisa. (2013) Georgy Berkeley. In Zalta (Ed.) (2016). Retrieved from http://plato.stanford.edu/archives/spr2013/entries/berkeley/.
- Berkeley, George. (1957) A Treatise Concerning the Principles of Human Knowledge. Forgotten Books.