John Locke (1632–1704) stands as one of the most pivotal figures of the 17th century, a polymath whose vast contributions spanned philosophy, political theory, theology, and education. Often hailed as the father of British Empiricism, Locke’s profound insights laid the groundwork for modern liberal thought and profoundly shaped our understanding of government, knowledge, and the human mind. This article delves into What Did John Locke Do, exploring the key aspects of his life, his groundbreaking works, and his enduring legacy.
Locke’s intellectual journey was marked by a commitment to reason and observation, principles that permeated his seminal Essay Concerning Human Understanding. In this work, he meticulously examined the human mind, arguing that our knowledge is derived from experience, a radical departure from prevailing nativist doctrines. He championed the idea of limited government in his Two Treatises of Government, advocating for natural rights and popular sovereignty, ideas that resonated deeply during the Enlightenment and beyond. His advocacy for religious toleration further cemented his status as a champion of individual liberty and intellectual freedom. Let’s explore the multifaceted contributions of this towering figure and understand what did John Locke do to earn his place in history.
1. Life and Intellectual Development
Born in the quaint village of Wrington, England, in 1632, John Locke’s early life was shaped by the tumultuous events of the English Civil War. His father, a legal clerk and Parliamentarian soldier, instilled in him values that likely contributed to his later political philosophy. Locke’s family, though not aristocratic, provided him with a solid foundation, allowing him to attend the prestigious Westminster School in London before securing a place at Christ Church, Oxford in 1652.
Oxford, during Locke’s time, was steeped in traditional scholastic philosophy, a system he found intellectually stifling. While he excelled academically and held various positions within the college after graduation, his intellectual curiosity gravitated towards medicine and natural philosophy – what we now recognize as science. He immersed himself in these fields, engaging in experiments and forging connections with leading scientific minds like Robert Boyle. This period saw the genesis of Essays on the Law of Nature, reflecting his early philosophical explorations developed during his teaching duties.
John Locke, a portrait showcasing the philosopher and his intellectual demeanor.
In 1667, Locke’s life took a significant turn when he moved to London and became associated with the influential Anthony Ashley Cooper, later the Earl of Shaftesbury. His roles within the household were diverse, ranging from tutor to Ashley’s son to acting as a physician. London provided a vibrant intellectual atmosphere where Locke further pursued his scientific and medical interests, collaborating closely with the renowned physician Thomas Sydenham and becoming a member of the newly established Royal Society in 1668. His medical expertise was even credited with saving Ashley’s life during a critical surgical operation.
Ashley’s prominent position in English politics opened doors for Locke to governmental roles, primarily concerning policies related to England’s colonies in America and the Caribbean. Crucially, this period marked the inception of his magnum opus, Essay Concerning Human Understanding. The initial drafts from 1671 signaled the beginning of a two-decade-long intellectual endeavor.
Political shifts in England led Locke to travel to France in 1675 for several years. Upon his return, the changing political landscape and Shaftesbury’s declining favor prompted Locke to write Two Treatises Concerning Government. Though published later in 1689, these treatises solidified his political philosophy advocating for limited government. Following Shaftesbury’s death, fearing political persecution, Locke sought refuge in the Netherlands. During this period of exile, he continued refining his Essay and penned Epistola de Tolerantia (Letter Concerning Toleration), published anonymously in 1689, reflecting his growing conviction for religious freedom after witnessing religious tensions in England, France, and the Netherlands.
The Glorious Revolution of 1688-1689 allowed Locke to return to England, where he published both the Essay and the Two Treatises. He found a home with Francis and Damaris Masham in Oates, Essex, developing a deep and lasting friendship with Damaris Masham, a philosopher herself. This period was remarkably productive, with Locke engaging in debates, including a significant one with Bishop Edward Stillingfleet on the Essay, and continuing to write on politics, toleration, philosophy, economics, and education.
In his later years, theology became a central focus, culminating in The Reasonableness of Christianity (1695), again published anonymously, arguing for a less dogmatic and more ecumenical form of Christianity. Despite lifelong health issues, Locke remained intellectually active until his death on October 28, 1704, at Oates. He was buried in High Laver, leaving behind a legacy defined by his profound intellectual contributions and unwavering commitment to reason and liberty.
2. The Foundational Project of Essay Concerning Human Understanding
The genesis of Locke’s Essay Concerning Human Understanding arose from a philosophical discussion with friends. Encountering roadblocks in their debate, Locke recognized a fundamental need to first understand the capacities and limitations of the human mind itself. He articulated this motivation in the Epistle to the reader: “…it was necessary to examine our own Abilities, and see, what Objects our Understandings were, or were not fitted to deal with.” (Epistle, 7).
This marked a paradigm shift in philosophical inquiry. Locke argued that before grappling with the complexities of the world, we must first understand how our minds acquire knowledge, what the scope of our understanding is, and what knowledge truly means. As he states in the Essay, his purpose is “to enquire into the Original, Certainty, and Extent of humane Knowledge; together, with the Grounds and Degrees of Belief, Opinion, and Assent.” (1.1.2, 42). Locke envisioned his role as an “Under-Labourer,” clearing the ground for the scientific advancements of figures like Robert Boyle and Isaac Newton by establishing a solid epistemological foundation.
The Essay is structured into four books, each contributing to this overarching goal. Book I refutes the notion of innate ideas, setting the stage for Book II, where Locke proposes that all knowledge originates from experience. Here, he details how even abstract concepts are derived from sensory input and mental operations. Book III, a diversion into language, highlights its crucial role and potential pitfalls in reasoning. Finally, Book IV delves into knowledge, belief, and opinion, defining knowledge as specific relationships between ideas and providing a framework for rational belief formation.
a. Ideas as the Building Blocks of the Mind
Locke’s pervasive use of the term “idea” in the Essay is explained in the opening chapter, emphasizing their fundamental role in his theory of mind and knowledge. He defines “idea” broadly as “whatsoever is the Object of the Understanding when a Man thinks…whatever is meant by Phantasm, Notion, Species, or whatever it is, which the Mind can be employ’d about in thinking.” (1.1.8, 47). Ideas, for Locke, are the primary entities the mind engages with.
However, the precise interpretation of “idea” remains debated. One interpretation views ideas as mental objects, representations of external objects existing within the mind. When we perceive an apple, we are essentially interacting with the idea of the apple. Another interpretation sees ideas as mental actions, the very act of perceiving the external world directly. While scholarly consensus leans towards the “mental object” interpretation, the debate underscores the complexity of Locke’s concept of ideas and their role in mediating our understanding of the world.
b. Against Innate Ideas: The Empiricist Stance
Book I of the Essay is a sustained critique of nativism, the doctrine that some ideas are inborn, pre-existing experience. Although Locke doesn’t explicitly name all his targets, figures like Herbert of Cherbury, René Descartes, the Cambridge Platonists, and certain Anglican theologians are considered likely proponents of the views he opposed. However, Locke’s primary aim in Book I is to establish the groundwork for his alternative empiricist account of knowledge acquisition detailed in Book II.
Nativism, as Locke addresses it, posits that humans possess innate mental content – ideas not derived from experience or constructed from experiential input. The prevalent form of nativism argued that God implanted specific ideas in minds at creation. Locke challenges both innate principles (e.g., “the whole is greater than the part,” moral maxims) and innate singular ideas (e.g., God, identity, substance). His central argument rests on the lack of universality of these supposedly innate ideas. He points out that children and individuals with intellectual disabilities do not possess complex innate thoughts, and ethnographic accounts reveal that various cultures lack concepts considered by nativists to be universally innate, such as the idea of God or universally accepted moral principles. This lack of universal presence, Locke argues, undermines the claim of divine implantation and supports the experiential origin of ideas.
It’s crucial to dispel a common misinterpretation of Locke’s anti-nativism, often stemming from his metaphor of the mind as a tabula rasa – a blank slate. This can misleadingly suggest that Locke believed the mind is entirely passive and devoid of inherent structure before experience. In fact, Locke acknowledges that the mind possesses innate faculties, predispositions, and inclinations. His anti-nativist claim is specifically directed against innate content – ideas present from birth. He maintains that these inherent mental capacities are only activated and directed once the mind begins to receive sensory input.
c. Acquiring Ideas Through Experience: Sensation and Reflection
Book II of the Essay provides Locke’s positive account of idea acquisition, the cornerstone of his empiricism. We possess a vast array of complex ideas, from everyday concepts like “orange juice” to abstract notions like “justice” and “infinity.” Locke’s fundamental claim is that all these ideas, ultimately, are rooted in experience: “Experience: In that, all our Knowledge is founded; and from that it ultimately derives itself. Our Observation employ’d either about external, sensible Objects; or about the internal Operations of our Minds, perceived and reflected on by ourselves, is that, which supplies our Understandings with all the material of thinking. These two are the Fountains of Knowledge, from whence all the Ideas we have, or can naturally have, do spring.” (2.1.2, 104).
Locke identifies two sources of experience: sensation (outer experience) and reflection (inner experience). Sensation provides ideas from the five senses – sight, hearing, touch, taste, and smell. Seeing a fern gives rise to the idea of “green,” hearing music produces ideas of “sound.” Reflection, a more internal process, involves observing the mind’s own operations. We are constantly engaged in mental activities – remembering, imagining, desiring, doubting, judging, choosing. Locke argues that by being aware of these internal operations, we acquire ideas of reflection, such as “memory,” “imagination,” “desire,” “doubt,” “judgment,” and “choice.”
Experience, through sensation and reflection, furnishes us with simple ideas, the fundamental, indivisible units of mental content. A simple idea is “uncompounded, [and] contains in it nothing but one uniform Appearance, or Conception in the mind, and is not distinguishable into different Ideas.” (2.2.1, 119). In contrast, complex ideas, like “orange juice” or “subway system,” are constructed by combining simple ideas. Locke proposes that complex ideas are compositional, built from simple ideas through mental operations. The idea of “orange juice” is a composite of simple ideas like “orange color,” “coolness,” “sweet taste,” and “acidic taste,” combined into a unified concept. This compositional nature extends to increasingly complex ideas, formed by further combinations.
This framework reveals the essence of Locke’s empiricism: all our ideas, every conceivable thought, can be ultimately broken down into simple ideas derived from experience. Book II is dedicated to substantiating this empiricism by examining mental faculties (memory, abstraction, volition) and demonstrating how even abstract ideas like “space,” “infinity,” “God,” and “causation” can be constructed from simple experiential ideas.
Locke categorizes complex ideas into three types: substances, modes, and relations. Ideas of substances represent things perceived as existing independently, such as “desk,” “sheep,” or “mountain.” This category also includes collective substances, groups of individual substances considered as wholes, like “town” (collection of buildings) or “army” (group of people). Locke also explores the idea of “substance-in-general,” questioning the underlying nature of substances. What are things like shoes or spoons made of? Leather and metal? But what are leather and metal made of? Matter? Locke concludes that our understanding of substance is inherently limited; we lack a clear idea of what truly underlies and gives rise to observable properties. Therefore, our ideas of substances remain somewhat obscure.
Ideas of modes are ideas of things dependent on substances. This category, less clearly defined in contemporary metaphysics, functions as a broad classification for ideas that are neither substances nor relations. Modes can be understood as features or modifications of substances: “such complex Ideas, which however compounded, contain not in them the supposition of subsisting by themselves, but are considered as Dependences on, or Affections of Substances.” (2.12.4, 165). Modes are further divided into simple modes and mixed modes. Simple modes are formed by repeating and combining a single simple idea, such as the idea of “unity.” The number “seven,” for instance, is a simple mode constructed by combining seven ideas of unity. Locke uses simple modes to explain our understanding of number, space, time, pleasure, pain, and cognitive functions. Mixed modes, on the other hand, combine simple ideas of different kinds. Many ideas fall into this category, most notably moral ideas. Concepts like “theft,” “murder,” “promise,” and “duty” are considered mixed modes.
Ideas of relations involve connections between two or more substances. The idea of “husband” is relational, requiring not just the idea of a man but also the idea of a spouse. Locke emphasizes the pervasive role of relations in our thinking. Even considering Elizabeth II as “Queen of England” involves relational thinking, as “queen” inherently implies a sovereign relationship to subjects. Locke explores relations extensively, particularly in understanding causation, space, time, morality, and identity.
Throughout his analysis of complex ideas, Locke consistently emphasizes their ultimate reducibility to simple ideas from sensation and reflection. The success of his empiricist theory hinges on its ability to account for the entirety of our mental content. While Locke’s analyses sometimes leave gaps to be filled by the reader, and some simple ideas, like “power” and “unity,” seem less directly derived from experience, his comprehensive attempt to ground all knowledge in experience remains a landmark achievement in epistemology.
Book II concludes with criteria for evaluating the quality of our ideas: clarity, distinctness, reality, adequacy, and truth. “Better” ideas are clear, distinct, real, adequate, and true, while “worse” ideas are obscure, confused, fantastical, inadequate, and false. Clarity and obscurity are likened to visual clarity. Distinctness and confusion relate to the individuation of ideas and their correspondence to specific words. Real ideas have a “foundation in nature,” while fantastical ideas are products of imagination. Adequacy and inadequacy concern how well ideas represent their intended archetypes. Truth and falsity pertain to the correctness of our understanding of ideas in relation to language and reality.
Locke applies these criteria to his categories of ideas. Simple ideas fare well, being directly caused by objects and generally clear and distinct. Ideas of modes and relations also tend to be good, as their archetypes are mental constructs, allowing for greater clarity and control. Ideas of substances, however, often fall short. Their archetypes are external objects, and our limited perceptual access and the complexity of substances lead to confused, inadequate, and potentially false ideas.
d. Language: A Tool and a Potential Trap
Book III of the Essay turns to language, a topic Locke initially considered a digression but recognized as crucial to understanding cognition. He views language as primarily a tool for communication, specifically for conveying our ideas to others. Locke asserts, “Words in their primary or immediate Signification, stand for nothing, but the Ideas in the Mind of him that uses them.” (3.2.2, 405). When we use words like “gold” or “carrot,” we are referring to our internal ideas of those things. He acknowledges the arbitrary and conventional nature of word-idea pairings.
While the primary function of words is to signify internal ideas, Locke concedes that words also have “secret reference” to two other things. Firstly, we intend our words to correspond to similar ideas in the minds of others for effective communication. Secondly, we often assume words refer to external objects themselves. However, Locke is skeptical of this latter assumption, considering it a potential source of error.
Book III further explores the complexities of language, including words for simple ideas, modes, substances, and the phenomenon of single words representing multiple ideas. He dedicates a chapter to “particles,” words like “is,” “and,” “but,” which don’t represent ideas directly but indicate relationships between them.
Locke identifies numerous ways language can lead to confusion and hinder knowledge. The arbitrary nature of word-meaning associations, the complexity of ideas words represent, and the tendency to use words without clear corresponding ideas all contribute to linguistic pitfalls. He notes that we are often taught words before grasping their meaning, and inconsistency in word usage and equivocation further compound the problems. The false assumption that words perfectly capture external reality is another significant source of error.
These linguistic issues, Locke argues, lead to widespread misuse of language, resulting in confused debates, especially in fields like science, politics, and philosophy, often devolving into mere verbal disputes. He provides examples: Cartesians conflating “body” and “extension,” physiologists disagreeing due to differing definitions of “liquor,” and Scholastic philosophers using terms like “prime matter” without a clear idea of what they signify.
Locke proposes remedies to mitigate language-related problems. The most crucial is to use words only when we possess clear, distinct ideas corresponding to them. He emphasizes the need for complete and consistent ideas and consistent word usage, avoiding equivocation. Finally, he advocates for clearly communicating word definitions to ensure shared understanding. While seemingly straightforward, Locke acknowledges the difficulty in consistently implementing these remedies.
e. Knowledge as Perceived Agreement or Disagreement of Ideas
In Book IV, Locke addresses knowledge and belief, building upon his account of idea acquisition. He famously defines knowledge as “the perception of the connexion and agreement, or disagreement and repugnancy of any of our Ideas.” (4.2.2, 525). Knowledge, for Locke, is the direct apprehension of relationships between ideas. Where this perception exists, there is knowledge; where it’s absent, we may have fancy, guess, or believe, but not true knowledge.
Locke elucidates “agreement and disagreement” through examples. Consider “white” and “black.” We immediately perceive their difference, their “disagreement,” and this perception constitutes knowing that “white is not black.” Similarly, knowing “Boise is in Idaho” involves perceiving a connection between the idea of Boise and the idea of Idaho. Locke identifies four types of agreement or disagreement:
- Identity or Diversity: Perceiving whether two ideas are the same or different (e.g., knowing “sweetness is not bitterness”).
- Relation: Perceiving relationships between ideas (e.g., knowing “7 is greater than 3”).
- Co-existence or Non-co-existence: Perceiving whether the idea of a property accompanies the idea of a thing (e.g., knowing “ice is cold”).
- Real Existence: Perceiving the agreement of an idea with actual existence (e.g., the Cogito, recognizing the connection between self and existence).
Locke distinguishes three “degrees” of knowledge in 4.2, representing different ways of knowing:
- Intuitive Knowledge: Direct, immediate perception of agreement between two ideas. This is the clearest and most certain form of knowledge, achieved “at the first sight of the Ideas together, by bare Intuition, without the intervention of any other Idea.” (4.2.1, 531).
- Demonstrative Knowledge: Indirect perception of agreement through intermediary ideas and a chain of intuitive steps. For example, understanding that the angles of a triangle sum to 180 degrees requires a geometric proof, a series of intuitively known relations. Demonstrative knowledge relies on a sequence of intuitive connections.
- Sensitive Knowledge: This degree, debated by Locke scholars, concerns our awareness of external objects causing our sensations. Locke questions whether it strictly qualifies as “knowledge.” Sensitive knowledge goes beyond mere probability but falls short of intuitive or demonstrative certainty. It involves the conviction that when we perceive, say, an orange, an external object is causing the sensation. Locke points to the qualitative difference between experiencing an orange and merely remembering it, suggesting a phenomenological assurance of an external cause in the former.
Locke addresses skepticism and the concern that his emphasis on ideas isolates us from the external world, the “veil of ideas” problem. If knowledge is only of ideas, how can we know anything about the external world itself? How can we be sure our ideas reliably represent external reality? Gilbert Ryle famously quipped that “nearly every youthful student of philosophy both can and does in his second essay refute Locke’s entire Theory of Knowledge,” highlighting the perceived vulnerability of Locke’s epistemology to skepticism. However, more recent scholarship offers more nuanced interpretations.
The interpretation of sensitive knowledge is crucial here. If it’s a relation between ideas and external objects, it seems to contradict Locke’s claim that knowledge is only between ideas. Interpretations of “idea” also matter. If ideas are mental acts of perception, as some argue, the connection to the external world is inherent in the definition of “idea,” potentially mitigating skeptical concerns.
Regardless of these interpretations, there’s consensus that Locke believed human knowledge is limited. Chapter 4.3, “Extent of Humane Knowledge,” emphasizes these limitations. Our problematic ideas of substances and the uncertain connection between ideas and external causes contribute to this limited scope.
However, Locke argues that our knowledge, though limited, is sufficient for our needs. Using the metaphor of a sailor’s line, he states: “‘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 Shoales, that may ruin him. Our Business here is not to know all things, but those which concern our Conduct.” (1.1.6, 46). We have enough knowledge for practical living, moral understanding, and even religious faith. Morality, in particular, is a domain where Locke believes we can attain demonstrative knowledge, as moral ideas are modes, which are clearer than ideas of substances. Recognizing the limits of knowledge is valuable, guiding intellectual inquiry towards fruitful areas and away from unsolvable questions.
Locke’s acknowledgment of limited knowledge led him to focus on judgment or opinion, belief states falling short of certainty. Given the limited scope of knowledge, probability becomes essential. Judgment, for Locke, is presumed agreement or disagreement between ideas, as opposed to perceived agreement in knowledge. He analyzes how we form opinions, the degrees of assent, and the role of testimony in belief formation, providing a comprehensive account of rational belief beyond the realm of certain knowledge.
3. Key Philosophical Themes in the Essay
Beyond its core epistemological project, the Essay encompasses a wide range of philosophical topics. However, it’s sometimes unclear whether Locke presents metaphysical theories or psychological descriptions. For example, is his account of personal identity a metaphysical definition of personhood or a description of how we attribute identity? Similarly, are primary and secondary qualities presented as a theory of perception or an illustration of idea formation? Despite these ambiguities, these “special topics” have significantly influenced subsequent philosophical discourse.
a. Primary and Secondary Qualities: Distinguishing Reality from Perception
Book II, Chapter 8 of the Essay explores the distinction between primary and secondary qualities, a concept already circulating at the time but given influential articulation by Locke. He defines a quality as a power in a body to produce ideas in us. A potato, for instance, has qualities that produce ideas of brownness, heat, shape, solidity, and size. Locke argues that these qualities are not all of the same kind.
He explains the distinction through a mechanistic theory of perception. Perception arises from motion and collision. Smelling a potato involves particles from the potato striking nasal nerves, triggering a chain reaction leading to the idea of smell. Seeing a potato involves particles hitting the retina, causing a similar chain reaction culminating in the idea of shape.
From this, Locke infers that objects must possess certain features to produce ideas, while others are not necessary. A mechanistic account requires objects to have shape, extension, mobility, and solidity (primary qualities) but not necessarily color, taste, sound, or temperature (secondary qualities). Primary qualities are inherent in bodies, features they cannot lack. Secondary qualities are not in bodies themselves but are powers of bodies, due to their primary qualities, to produce certain ideas in us. When we say a potato is solid, we refer to a primary quality. When we say it smells earthy, we refer to a secondary quality, a power to produce that smell in us.
This leads to Locke’s claim about resemblance: “Ideas of primary Qualities of Bodies, are Resemblances of them, and their Patterns do really exist in the Bodies themselves; but the Ideas, produced in us by these Secondary Qualities, have no resemblance of them at all.” (2.8.14, 137). Our ideas of primary qualities (shape, extension, etc.) accurately represent mind-independent features of objects. However, ideas of secondary qualities (smell, temperature, taste) do not resemble anything mind-independent in the object, only the object’s power to produce those sensations in us.
b. Mechanism: The World as a Machine
Around Locke’s time, the mechanical philosophy was gaining prominence, proposing that the physical world is composed of tiny, indivisible particles (corpuscles) with primary qualities (shape, size, motion). All physical phenomena were to be explained by corpuscles and their interactions.
Locke encountered mechanism at Oxford and became acquainted with its proponents. He largely embraced it, considering it the best explanation of nature. The primary/secondary quality distinction aligns with mechanistic accounts of perception. Locke often describes material objects as collections of corpuscles.
However, the Essay presents a nuanced view of mechanism. While endorsing it in some respects, Locke also raises critical points and acknowledges its limitations. His critique has two strands. First, mechanism struggled to explain certain observed phenomena like magnetism, chemical processes, biological functions (fermentation), and universal gravitation (Newton’s discovery). Locke suggests that God might have “superadded” non-mechanical powers to matter, like gravitation, and even the capacity for thought.
Second, Locke identifies theoretical problems within mechanism. Cohesion is a major issue. Why do corpuscles stick together to form solid objects? Mechanism struggled to explain the cohesion of bodies and even the cohesion of individual corpuscles themselves. Furthermore, Locke questions our understanding of motion transfer by impact. How does one corpuscle make another move upon collision? Mechanism lacked a satisfactory explanation.
Despite these critiques, Locke remained cautiously optimistic about mechanism. This mixed stance has led to scholarly debates about Locke’s true position on mechanism and his motivations for discussing it.
c. Volition and Agency: The Power of Will
Book II, Chapter 21 of the Essay explores volition and free agency. Humans, unlike inanimate objects, make decisions and control actions, experiencing a sense of freedom and choice. Locke calls this power the will. He grapples with defining this power and what constitutes free or voluntary choice.
Locke first defines freedom: we are free to do what we will and are physically able to do. If I want to jump in a lake and can, I’m free to do so. If I’m pushed into the lake against my will, or if I want to jump but am physically unable, I’m not acting freely.
However, the question of whether the will itself is free remains. Is the will determined by external factors, or can it independently choose? Locke initially suggests the will is determined, primarily by “uneasiness”: “What is it that determines the Will in regard to our Actions? … some (and for the most part the most pressing) uneasiness a Man is at present under. That is that which successively determines the Will, and sets us upon those Actions, we perform.” (2.21.31, 250-1). Uneasiness arises from the absence of something perceived as good, creating desire. Choosing to eat pizza, for example, is driven by the uneasiness of hunger or craving, generating a desire for pizza that determines the will.
Locke qualifies this determinism with the concept of “suspension.” From the second edition of the Essay onwards, he argues that while the strongest uneasiness usually determines the will, we possess the power to suspend desire satisfaction: “For the mind having in most cases, as is evident in Experience, a power to suspend the execution and satisfaction of any of its desires, and so all, one after another, is at liberty to consider the objects of them; examine them on all sides, and weigh them with others.” (2.21.47, 263). We can pause before acting on our strongest desire, consider alternatives, and potentially shift our desires. However, it remains debated whether this suspension of judgment itself is freely chosen or determined by another desire (e.g., the desire to deliberate). Interpretations vary on whether Locke’s “suspension” offers a robust form of free will.
d. Personhood and Personal Identity: What Makes “Me” “Me”?
Locke was a pioneer in addressing personal identity, exploring what makes us the same person over time. This discussion occurs in Book II, Chapter 27, within a broader treatment of identity conditions. The core question: what makes the person who performed past actions and will perform future actions the same person as “me” now?
Personal identity was a significant issue in Locke’s time due to religious doctrines of afterlife rewards and punishments. For these doctrines to be meaningful, the person rewarded or punished must be the same person who lived a virtuous or sinful life, even after death and potential bodily resurrection.
Locke’s account has two components: a negative project against substance-based personal identity and a positive project based on consciousness. His positive view defines a person as “a thinking intelligent Being, that has reason and reflection, and can consider itself as itself, the same thinking thing in different times and places; which it does only by that consciousness, which is inseparable from thinking, and as it seems to me essential to it.” (2.27.9, 335). Personal identity, for Locke, is rooted in the continuity of consciousness, the ability to recognize past experiences as one’s own. My sense of being the same person as my childhood self stems from recognizing a continuous stream of consciousness connecting past experiences to my present self-awareness.
Locke argues that consciousness-based identity renders substance-based accounts (like the soul theory) unnecessary and problematic. He presents thought experiments: if a soul’s memories are erased and replaced, or if consciousness is transferred between souls, personhood follows consciousness, not the soul.
Locke’s account aimed to be theologically neutral and move away from purely metaphysical explanations. However, it faces challenges, particularly regarding the role of memory and the precise definition of “consciousness” in his theory. Despite these issues, Locke’s consciousness-based approach to personal identity remains influential in contemporary philosophy.
e. Real and Nominal Essences: Knowing What Things Are
Locke’s distinction between real and nominal essences is a key element of his metaphysics. Scholastic philosophers sought to understand the “essences” of things, their underlying nature explaining their properties. Locke considered this project misguided, arguing that real essences are unknowable to humans. He proposed focusing instead on nominal essences, which are accessible to us.
Real essence, for Locke, is “the real constitution of any Thing, which is the foundation of all those Properties, that are combined in, and are constantly found to co-exist with [an object]” (3.6.6, 442). For Scholastics, this was substantial form; for mechanists, it was corpuscular structure. Locke leans towards the mechanistic view but emphasizes that real essences are unknown and beyond our grasp. Nominal essences, in contrast, are knowable – collections of observable properties. The nominal essence of gold includes yellowness, weight, malleability, etc.
Locke uses the analogy of a complex clock. We see the clock’s face and hands (nominal essence), but the internal mechanisms (real essence) are hidden. Similarly, we observe the nominal essence of a dandelion (color, smell) but not its underlying real essence.
Locke’s view has implications for classification. We group things based on nominal essences, not unknown real essences. This means our classifications might not reflect real distinctions in nature. Locke is a conventionalist about species and types; we impose these categories based on observable similarities, not inherent natural kinds.
f. Religious Epistemology: Faith and Reason
Religious epistemology, understanding God and religious duties, was highly contested in Locke’s era. The English Civil War involved religious disagreements. Locke, in 4.18 of the Essay, addresses faith and reason and their domains. Reason, for Locke, is discovering certainty or probability through natural faculties. Faith is accepting something as certain or probable based on divine communication. Believing a potato chip is salty through taste is reason; believing Joshua stopped the sun based on Bible reading is faith.
While seemingly distinct, Locke subtly subordinates faith to reason: “Whatever GOD hath revealed, is certainly true; no Doubt can be made of it. This is the proper Object of Faith: But whether it be a divine Revelation, or no, Reason must judge; which can never permit the Mind to reject a greater Evidence to embrace what is less evident, nor allow it to entertain Probability in opposition to Knowledge and Certainty.” (4.18.10, 695). Reason judges whether something is genuinely divinely revealed. Revelation contradicting reason should be rejected. Determining divine revelation requires reason. Locke criticizes “enthusiasm,” religious fervor neglecting reason. He advocates for reason’s crucial role in religious belief.
Locke’s position is moderately religious, valuing faith but emphasizing reason’s limits and authority in assessing faith claims. This framework becomes important for his views on religious toleration.
4. Political Philosophy: Liberty and Governance
Locke lived through turbulent English political times, influencing his political thought. He is renowned for advocating religious toleration and limited government, radical ideas in his era, now widely accepted.
a. Two Treatises of Government: Justifying Limited Government
Locke’s Two Treatises of Government (1689) were initially thought to defend the Glorious Revolution, but were written earlier. Nevertheless, they provide a philosophical basis for limited government favored by William’s supporters.
The First Treatise critiques Robert Filmer’s Patriarcha, arguing for divine right monarchy based on Adam’s God-given dominion. Locke refutes this historically and distinguishes types of authority Filmer conflates.
The Second Treatise presents Locke’s positive political theory. He posits a pre-political state of nature where individuals possess natural rights given by God, including the right to life and liberty. This state, lacking government, is unstable due to potential conflicts. Government arises through a social contract: individuals relinquish some rights to a central authority to gain protection and stability, while retaining other rights.
Governments are instituted by citizens and obligated to them. Rulers have limited power, respecting individual rights. Citizens retain the right to revolt against governments that fail to protect rights or overstep authority.
Locke’s theory of natural rights and social contract justifies limited government, individual rights, and the right to revolution against unjust rule, ideas profoundly influential to this day.
b. Property: Labor and Ownership
Locke’s Second Treatise includes an influential theory of private property. God gave the world to humanity in common for sustenance and enjoyment. However, individuals can justly appropriate parts of the world for private use. Locke argues for a right to private property acquisition.
Property is acquired by mixing labor with natural resources. Picking grapes, farming land, or making a table from forest wood creates ownership. Locke imposes two provisos: the Waste Proviso (don’t let property spoil) and the Enough-And-As-Good Proviso (leave enough and as good for others).
With currency and government, property changes. Durable currency allows wealth accumulation, seemingly diminishing the Waste Proviso. Governments regulate property. Locke addressed property within a commonwealth, but his state-of-nature property acquisition theory is more famous.
c. Toleration: Religious Freedom and Limits
Locke’s advocacy for religious toleration, articulated in Epistola de Tolerantia (1689), stemmed from his experiences in England, France, and the Netherlands. He argued for religious freedom, against state-imposed religion. His Letter Concerning Toleration was prompted by Louis XIV’s revocation of the Edict of Nantes, persecuting French Protestants.
Locke’s toleration argument connects to his epistemology and political theory. Epistemologically, our knowledge is limited, especially in religion. Rulers are not more likely to know the true religion. Forcing religious conformity is unjustified; individuals should freely pursue truth. Religious diversity is potentially beneficial.
Politically, government’s purpose is social order, not religious salvation. Enforcing religion is outside government’s scope and ineffective, as belief is internal. Forced conformity is also disruptive.
However, Locke’s toleration had limits. He excluded the intolerant (those imposing their views), groups threatening public safety (including Catholics, due to Papal allegiance), and atheists (deemed untrustworthy without belief in afterlife accountability). Despite these limitations, Locke’s advocacy for toleration was groundbreaking.
5. Theology: The Reasonableness of Christianity
Locke’s The Reasonableness of Christianity (1695) argues for the rationality of Christian belief. He aims to show that Christianity, in its essentials, is consistent with reason and evidence.
Locke argues that Jesus provided sufficient evidence of divine messenger status through fulfilling prophecies and performing miracles. He emphasizes the importance of testimony for believing in miracles. He examines the nature and value of testimony, a topic of philosophical interest in itself.
Locke controversially minimized the requirements for Christian salvation. He argued that believing Jesus is the Messiah is the sole essential belief for salvation. Other doctrines, particularly those in the Epistles, are less crucial and prone to disagreement. The core Christian tenet is simple faith in Jesus as Messiah.
This minimalist approach aligned Locke with latitudinarians within the Church of England, seeking a less divisive Christianity, free from sectarian dogmatism. Locke’s radical reduction of essential Christian beliefs was part of this irenic movement.
6. Education: Shaping Young Minds
Locke was considered an educational expert, having taught at Oxford and privately tutored. His Some Thoughts Concerning Education (1693), originating from letters to Edward Clarke, outlines his progressive educational philosophy.
Locke rejected rote memorization of classical languages and corporeal punishment, common in 17th-century education. He stressed practical knowledge and engaging learning. He advocated for allowing children some self-direction and pursuing their interests, foreshadowing modern pedagogy.
Locke emphasized early childhood education’s importance in shaping habits and character. Some Thoughts Concerning Education focuses on moral education, cultivating virtue and industry. He favored understanding-based moral development over authoritarian methods, aiming to instill a self-directed moral sense in children.
7. Locke’s Enduring Influence
Locke’s Essay was quickly recognized as philosophically significant, integrated into Oxford and Cambridge curricula, and translated into Latin and French, gaining European readership. The Two Treatises also became influential, particularly during the American and French Revolutions, inspiring movements for representative government.
Locke, alongside Newton, became an Enlightenment symbol, embodying reason and progress. Newtonian science revealed nature’s workings; Lockean philosophy illuminated the human mind, leading to social and political reform. Voltaire championed Locke’s ideas of reason, toleration, and limited government. Locke also inspired Deism, influencing figures like Anthony Collins and John Toland.
Locke is considered the founder of British Empiricism, shaping 18th and 19th-century Anglophone philosophy. However, successors like Berkeley, Hume, and Reid critically engaged with his ideas. Despite critiques, Locke remains a central figure in Western philosophy, with contemporary scholarship offering renewed appreciation for his contributions.
8. References and Further Reading
a. Locke’s Works
- Laslett, P. [ed.] 1988. Two Treatises of Government. Cambridge: Cambridge University Press.
- Locke, J. 1823. The Works of John Locke. London: Printed for T. Tegg (10 volumes).
- Locke, J. The Clarendon Edition of the Works of John Locke, Oxford University Press, 2015. This edition includes the following volumes:
- Nidditch, P. [ed.] 1975. An Essay Concerning Human Understanding.
- Nidditch, P. and G.A.J. Rogers [eds.] 1990. Drafts for the Essay Concerning Human Understanding.
- Yolton, J.W. and J.S. Yolton. [eds.] 1989. Some Thoughts Concerning Education.
- Higgins-Biddle, J.C. [ed.] 1999. The Reasonableness of Christianity.
- Milton, J.R. and P. Milton. [eds.] 2006. An Essay Concerning Toleration.
- de Beer, E.S. [ed.] 1976-1989. The Correspondence of John Locke. (8 volumes).
- von Leyden, W. [ed.] 1954. Essays on the Law of Nature. Oxford: Clarendon Press.
b. Recommended Reading
The following are recommendations for further reading on Locke. Each work has a brief statement indicating the contents
- Anstey, P. 2011. John Locke & Natural Philosophy. Oxford: Oxford University Press.
- A thorough examination of Locke’s scientific and medical thinking.
- Ayers, M. 1993. Locke: Epistemology and Ontology. New York: Routledge.
- A classic in Locke studies. Explores philosophical topics in the Essay and discusses Locke’s project as a whole. One volume on epistemology and one on metaphysics.
- Chappell, V. 1994. The Cambridge Companion to Locke. Cambridge: Cambridge University Press.
- A series of essays focusing on all aspects of Locke’s thought.
- LoLordo, A. 2012. Locke’s Moral Man. Oxford: Oxford University Press.
- An exploration and discussion of themes at the intersection of Locke’s moral and political thought. Focuses particularly on agency, personhood, and rationality.
- Lowe, E.J. 2005. Locke. New York: Routledge.
- An introductory overview of Locke’s philosophical and political thought.
- Mackie, J.L. 1976. Problems from Locke. Oxford: Oxford University Press.
- Uses Locke’s work to raise and discuss a number of philosophical issues and puzzles.
- Newman, L. 2007. The Cambridge Companion to Locke’s Essay Concerning Human Understanding. Cambridge: Cambridge University Press.
- A series of essays focusing on specific issues in Locke’s Essay.
- Pyle, A.J. 2013. Locke. London: Polity.
- An excellent and brief introduction to Locke’s thought and historical context. A very good place to start for beginners.
- Rickless, S. 2014. Locke. Malden, MA: Blackwell.
- An introductory overview of Locke’s philosophical and political thought.
- Stuart, M. 2013. Locke’s Metaphysics. Oxford: Oxford University Press.
- An in-depth treatment of metaphysical issues and problems in the Essay.
- Waldron, J. 2002. God, Locke, and Equality: Christian Foundation of Locke’s Political Thought. Cambridge: Cambridge University Press.
- An examination of some key issues in Locke’s political thought.
- Woolhouse, R. 2009. Locke: A Biography. Cambridge: Cambridge University Press.
- The best and most recent biography of Locke’s life.
Author Information
Patrick J. Connolly Email: [email protected] Lehigh University U. S. A.
