An Essay Concerning Human Understanding

1. Words are Arbitrary Signs of Ideas, Essential for Society.

There is no natural connection between particular sounds and particular ideas (if there were, there would be only one human language); but people arbitrarily chose to use such and such a word as the mark of such and such an idea.

Social instrument. God designed man as a sociable creature, equipping him with language as the great instrument and common tie of society. This required not only the ability to make articulate sounds, but also to use these sounds as signs of internal conceptions—ideas in one's own mind—to convey thoughts to others. Without this capacity, individual thoughts would remain locked within, invisible and hidden.

Arbitrary connection. The link between a specific sound (a word) and the idea it represents is not inherent or natural; it is a matter of human choice and convention. This arbitrary imposition means that words primarily and immediately signify only the ideas in the mind of the speaker. When one speaks, the goal is for those sounds to mark the speaker's ideas and make them known to the hearer, implying a shared understanding of these chosen signs.

Personal meaning. Each individual, from a child learning "gold" to a scholar, applies words to their own unique ideas, however imperfectly formed. While men secretly suppose their words refer to ideas in the hearer's mind and the reality of things, the immediate signification remains the speaker's own ideas. Words learned before their corresponding ideas can become mere "insignificant noise," highlighting the crucial connection between sound and idea for meaningful communication.

2. General Terms are Human Inventions, Not Properties of Reality.

Generality and universality are not properties of reality itself; rather, they are something that the understanding has invented for its own convenience, and they apply only to ·verbal and mental· signs - words and ideas.

Necessity of generality. Although all existing things are particulars, most words in all languages are general terms. This is not merely convenient but inevitable, as it is impossible to have a separate name for every particular thing encountered. Such a multitude of names would overwhelm memory, hinder communication, and offer little utility for advancing knowledge, which often requires grouping things into sorts.

Abstraction process. General words are formed by making them signs of general ideas, which themselves become general through abstraction. This involves separating from complex ideas the unique circumstances of time, place, and other features that tie them to a particular existence. By retaining only what is common to many individuals, the mind creates an abstract idea fitted to represent a multitude, such as forming the idea of 'man' by leaving out what is unique to Peter or Paul.

Mental constructs. The entire system of genera and species, often debated in academic circles, is simply a matter of more or less comprehensive abstract ideas with names tied to them. These general items are created by the human understanding for its own convenience, serving as signs to represent many particulars. Their meaning is a relation added by the mind, not an inherent property of things themselves, which are always particular in their existence.

3. Nominal Essences (Our Ideas) Define Species, Not Unknown Real Essences.

So the first item is equivalent to the last: the abstract idea for which the name stands, and the essence of the species, is one and the same.

Two kinds of essence. Locke distinguishes between two types of essences: the nominal essence and the real essence. The nominal essence is the abstract idea to which a general name is attached, serving as the measure and boundary of a sort or species. The real essence, conversely, is the internal constitution of a thing—the real but usually unknown inner nature from which its perceptible qualities depend.

Human classification. While nature produces things with similarities, the act of sorting them into species under general names is primarily the work of the understanding. We attend to observed similarities, form abstract general ideas, and use these as patterns. A particular thing is classified into a species, and given its name, if it conforms to the abstract idea associated with that name. Thus, the essences of species, as we pick them out and label them, are these abstract ideas in our minds.

Ignorance of real essences. We do not, and often cannot, know the real essences of substances. Consequently, we cannot use these unknown internal constitutions as the basis for our classifications. To claim that nature sorts all existing individuals into species by precise, distinct real essences would require knowledge we lack, and would struggle with phenomena like monstrous births or the varying properties found even within things of the same nominal species. Our classifications are practical tools, not perfect reflections of nature's hidden order.

4. Simple Ideas are Indefinable and Least Ambiguous.

Defining is really nothing but showing the meaning of one word through several others no one of which signifies the same thing; ·so the terms of a definition must jointly signify the idea that the defined word signifies·; but different terms of a definition, signifying different ideas, cannot jointly represent an idea that is simple and thus has no complexity at all.

Limits of definition. The names of simple ideas, unlike those of complex ideas, cannot be defined. A definition aims to explain a word's meaning by using several other words, each signifying a different idea, which together compose the meaning of the defined term. However, a simple idea, being a single, uncompounded perception, has no constituent parts that can be separately signified by other words.

Sensory origin. Simple ideas are acquired solely through the impressions objects make on our minds via the appropriate sensory inlets. If a simple idea has not been received through sensation, no amount of verbal explanation or definition can produce that idea in the mind. For instance, words cannot convey the idea of 'light' to a congenitally blind person, nor the taste of a pineapple to someone who has never tasted it, beyond vague resemblances to other known sensations.

Clarity and certainty. Despite their indefinability, the names of simple ideas are generally the least doubtful and uncertain in their meanings. Because each stands for a single, uncompounded perception, there is little room for misunderstanding or disagreement among people. One either comprehends the meaning precisely or recognizes one's ignorance, without the ambiguity that arises from combining multiple ideas or referring to unknown real essences.

5. Mixed Modes are Arbitrary Mental Constructs, Their Essences Perfectly Knowable.

In its complex ideas of mixed modes, the mind permits itself not to follow the existence of things exactly.

Mind's creation. The abstract ideas, or essences, of mixed modes are entirely the workmanship of the understanding. Unlike simple ideas, which are passively received from external objects, or substances, which are supposed to conform to real existences, the mind actively selects and combines simpler ideas to form complex ideas of mixed modes. These are made without direct patterns or reference to any real existence in nature.

Arbitrary formation. The mind exercises great freedom in constructing mixed modes, uniting collections of ideas to suit its own notions and conversational purposes. For example, the ideas of 'sacrilege' or 'adultery' can be framed and named, thus constituting species, before any such actions have ever been committed. This arbitrary nature means that the mind does not check these ideas against existing things, but rather creates archetypes that serve its own ends, such as the convenience of communication.

Nominal and real essence. For mixed modes, the nominal essence and the real essence are always the same. Since these abstract ideas are mental constructs, not referred to external reality, there is no supposition of anything beyond the complex idea the mind has formed. All properties and relations of a mixed mode species depend solely on this abstract idea, making its essence perfectly knowable and, consequently, morality capable of demonstration.

6. Substance Names Refer to Unknown Real Essences, Leading to Uncertainty.

But since he doesn’t know what that real essence consists in, what he connects malleableness with in his mind is not really that unknown essence but only the sound ‘gold’ that he puts in place of it.

Double reference. The names of substances, in their ordinary use, carry a double reference. They immediately signify the collection of simple ideas (perceptible qualities) found to coexist in a substance, forming its nominal essence. However, they are also tacitly supposed to refer to the substance's real constitution—the unknown internal structure from which all its properties flow. This secret mental assumption creates significant uncertainty.

Unknowable standard. When substance names are taken to stand for these unknown real essences, their application becomes inherently uncertain. It becomes impossible to definitively know which particular things truly possess the real essence of 'gold' or 'antimony' because we have no idea of what that essence is. This reliance on an unknowable standard means the meanings of substance names cannot be precisely corrected or established by those standards.

Varied ideas. Even when substance names are understood to signify collections of perceptible qualities (nominal essences), uncertainty persists. The simple ideas united in a single substance are numerous, and individuals often select different subsets of these qualities to form their complex ideas. This leads to different people associating different complex ideas with the same substance name, making its meaning variable and imprecise, especially in philosophical discourse where exactness is crucial.

7. Particles Reveal the Mind's Connections, Crucial for Coherent Discourse.

The words the mind uses to signify how it is connecting the various affirmations and negations that it is bringing together into a single continued reasoning or narration are generally called particles.

Beyond naming ideas. In addition to words that name ideas, language employs many others to signify how the mind connects ideas or propositions. These "particles" are not names of ideas themselves but rather indicators of the mind's operations, such as affirming, denying, restricting, distinguishing, or emphasizing. They are essential for showing the relations and dependencies between thoughts, enabling coherent and methodical reasoning.

Grammar's neglect. While grammarians meticulously classify parts of speech like nouns and verbs, the true "significancy" and force of particles are often overlooked. Understanding their proper use requires a diligent scrutiny of the mind's various "postures"—the subtle ways it views, turns, limits, and connects thoughts. This internal observation is key to mastering their application and avoiding confusion in communication.

Multifaceted meanings. Due to the vast array of mental connections and indications, and the limited number of corresponding particles in most languages, many particles acquire multiple, sometimes almost opposite, meanings. For instance, the particle "but" can signify a halt in thought, a limitation, a supposition of something amiss, a direct opposition, or even a logical connection in a syllogism. Their precise interpretation depends heavily on context and the speaker's intended mental posture.

8. The Absence of Abstract Names for Substances Betrays Our Ignorance of Their Real Essences.

For our ideas of substances we have very few if any abstract names.

Abstract vs. concrete. Language commonly distinguishes between abstract names (substantives) and concrete names (adjectives) for simple ideas, modes, and relations. For example, 'whiteness' is abstract, 'white' is concrete; 'justice' is abstract, 'just' is concrete. This linguistic pattern reflects a difference in how we conceive these ideas, allowing us to affirm one abstract idea of another in a concrete way (e.g., "A man is white," not "Humanity is whiteness").

Substances' peculiarity. However, for substances, there are very few, if any, commonly accepted abstract names. While scholastic philosophers attempted to coin terms like 'animality' or 'humanness,' these rarely gained widespread currency among intelligent people. This scarcity is a significant observation, suggesting a tacit confession by mankind that they lack clear ideas of the real essences of substances.

Ignorance revealed. If men truly had distinct ideas of the real essences of substances, they would likely have created abstract names for them, just as they did for simple ideas and modes. The reluctance to coin terms like 'goldenness' or 'stonehood' indicates an awareness of their ignorance regarding the underlying, unknown internal constitutions of these things. This linguistic gap underscores the fundamental difference in our knowledge of substances compared to our self-created ideas of modes.

9. Language's Imperfections and Abuses Hinder Knowledge and Fuel Disputes.

I’m inclined to think that if the imperfections of language, as the instrument of knowledge, were more thoroughly weighed, a great many of the controversies that make such a noise in the world would cease, and there would be a more open road than we now have to knowledge, and perhaps to peace also.

Natural imperfections. Language, by its very nature, is prone to imperfections that make many words doubtful and uncertain in meaning. These arise from:

• The complexity of ideas words represent.
• The lack of natural standards for mixed modes.
• The unknowable nature of real essences for substances.
• The discrepancy between a word's meaning and a thing's real essence.
  These inherent flaws mean words often fail to evoke the same precise idea in the hearer as in the speaker.

Wilful abuses. Beyond natural imperfections, men commit several "wilful faults" that further obscure language. These include:

• Using words without clear, distinct ideas.
• Inconstancy in word usage, shifting meanings within a discourse.
• Intentional obscurity through jargon or undefined terms.
• Mistaking words for things, assuming noun phrases correspond to real entities.
• Attempting to make words signify unknowable real essences.
• Confidently assuming others mean the same by a word as oneself.

Obstacle to truth. These imperfections and abuses significantly hinder the advancement of knowledge and fuel endless disputes. Instead of clarifying truth, language is often employed to darken it, unsettle rights, and render morality and religion unintelligible. Many controversies, especially in academic and theological realms, are "merely verbal," stemming from differing interpretations of words rather than substantive disagreements about things themselves.

10. Clarity in Language Requires Defined Ideas and Adherence to Common Usage.

To provide some remedy for the defects of speech that I have mentioned, and to prevent the troubles that follow from them, I think it would be useful to conform to the following rules.

Remedies for clarity. While a complete reform of language is impractical, those who genuinely seek truth must strive for clarity. To mitigate the natural imperfections and avoid the abuses of words, certain rules are essential. These are not for everyday chatter but for serious philosophical inquiry and the pursuit of knowledge, where precision is paramount.

Three crucial rules:

• Use no word without a meaning: Every word employed must correspond to a clear and distinct idea in the speaker's mind. Using words as mere sounds, without determinate ideas, renders discourse meaningless and hinders true understanding.
• Ensure ideas are determinate: For simple ideas, they must be clear and distinct; for complex ideas, they must be precise collections of simple ideas, firmly settled in the mind. This exactness, though demanding, is vital for avoiding obscurity and confusion, especially in moral and scientific discourse.
• Conform to common usage: Speakers should endeavor to align their word meanings with common usage in their language. Words are a shared medium of communication, and arbitrary private meanings thwart understanding, necessitating awkward interruptions for explanation.

Defining meanings. When clarity is needed, especially for new words or new senses of old words, one must explicitly declare their meaning. For simple ideas, this involves pointing to an object or presenting it to the senses. For mixed modes, definition is the primary and most effective method, as their essences are mental constructs. For substances, the challenge is greater due to the unknowable real essences, but the goal remains to align ideas with existing things as closely as possible.