An Essay Concerning Human Understanding

Because humans live in their heads—their minds full of many thoughts—a natural progression is that they should find a way to communicate those thoughts with one another. Words provided a natural form of communication, despite their failure at times to perfectly describe an idea. Locke argues that thoughts must come before words. Otherwise, the individual produces only sound; an individual cannot endow words with meaning until they represent an idea. Words operate on the assumption that others attribute the same meanings to the terms and that they are true.

Additionally, words can conjure ideas in others’ minds. Simply by saying the word “bird,” another person manifests an image of a bird in their mind. However, words present potential pitfalls. One problem with language is that many people know and use words without fully grasping their meaning. Another issue is that words can incite different emotions and reactions in different people. The same words may not have the same effect on two different people.

Humans are incapable of assigning names to every individual body and object in the world. Locke argues that the world simply has too many things to name. Not only would this be impossible; it would be impractical. He suggests that there is no need to apply names to every single substance; doing so would contribute nothing to greater scientific endeavors. Instead, group names or general terms are more useful. For concepts like countries, rivers, and geographical locations, general names are extremely useful. Locke cites the example of sheep. A farmer has no need to name every individual sheep, but the blanket term “sheep” is handy when referencing individual animals in the flock.

The essence of something aligns it with its general term. One understands a man as part of the general term “men” because of his essence. Locke proposes two important considerations for essences. First, essences represent “the real internal” (401). They are present in everything from the beginning. Second, plants and animals belong to genus or species, but abstract essence gives them the constitution and qualities to determine their category.

When a simple idea has a name, the mind conjures the image of something real and tangible. In addition, a name conjures an object’s essence. Locke struggles to explain what a word is, but he suggests that a word itself is not a definition. Humans define words only by using other words. Because words signify ideas, this means that ideas are defined only by other ideas. Once an idea is broken down into its most basic, simple ideas, those simple ideas cannot be further defined.

Locke bemoans the slipperiness of language and criticizes philosophers for using language inexactly. Because words cannot define simple ideas, sensory expression—the very thing that initiates ideas in the first place—must define them. Complex ideas require language to achieve composition.

Mixed modes like “murder” have their roots in the abstract. Humans do not necessarily need to see examples of these ideas to grasp them. The mind invents the essences that make up these concepts. Locke suggests that this process is simple. The mind selects a number of ideas and finds a connection among them, packaging them together with a name. As examples, he cites patricide and adultery. Locke argues that people do not need to see these actions take place to understand their essence. However, he cautions that it is a mistake to think that the mind groups ideas together at random. Locke argues that the chief aim of the mind is communication. It groups ideas together and names them for the purpose of language. In turn, names help preserve the idea and carry it forward.

Locke moves on to the simple subject of substances and their names. Although humans on Earth have only one sun, they understand that the sun has an essence with certain qualities that might apply to other things. Essences help humans categorize and make sense of the world. “Real” essences are the observable qualities that make something what it is, while nominal essences are abstract. Locke provides a lengthy description of how these two essences work within his own body. He points to the real essences that indicate that he is a human male. He explains, however, that if these essences were stripped away—for example, if he became sick and lost his ability to think—he is still a human male because of his nominal essence, the abstract quality that ties him to his species. For this reason, nominal essences are more important than real essences. Because all ideas of categorization and naming emerge from the mind through abstract thought, words fail to completely capture the nature of nominal essence.

In this chapter, Locke compares language to the popular scientific theory of his day: particles, or corpuscles. Locke uses the word “particles” to mean smaller words that connect ideas; he suggests that these words show connection and meaning. Locke’s particles are difficult to define. He uses the word “but” as an example and reveals how this singular conjunction requires a deep and complex definition.

Locke describes a person as both their category and their essence. For example, if an individual is rational, that person may be described as such. “Rational,” on its own, is an essence. Locke argues that an essence like “rational” cannot define larger ideas like the category of “man” because the essence may not apply to everyone within the category. Substances do not receive abstract names because they are concrete.

Throughout Book 3, Locke remarks on the inexactness of words. Locke proposes two uses of language: to record thoughts and to communicate ideas. Words are slippery; they do not always fully convey their ideas, and their impreciseness spreads “doubtfulness and uncertainty” (460). Words signifying mixed modes, or abstract ideas, are difficult for individuals to grasp. Locke compares this to trying to teach children new ideas; teachers often use visual aids to explain what something is. However, a teacher cannot present a visual for many abstract ideas—certainly none that convey a concept’s complexity.

Locke returns to the example of gold. He asserts that a scientist may not view gold in the same context as a child. The idea is more complex than its essence. Locke bemoans the imperfection of language, explaining that philosophy requires exact terms.

In this chapter, Locke explores the other side to the problem with language: how people use (or misuse) words. He begins by criticizing those who use words without fully understanding the ideas they represent or use words without signifying any ideas at all. Locke outlines his frustration with the misuse of language. He chides those who flippantly use words such as “wisdom, glory, [and] grace” (474), which signify abstract ideas. Other abuses include the tendency to use words inconsistently and the compulsion to be intentionally confusing. However, this frustration does not extend to the use of figurative language. The philosopher recognizes the importance of beauty, entertainment, and art. He suggests that using language for artistic purposes only contributes to its meaning and does not indicate a fault.

Locke understands that he will never be able to impose a universal and precise language on all of humanity. Such an undertaking would be ridiculous and futile. Instead, he argues that philosophers and “those who pretend seriously to search after or maintain truth” should consider their words more carefully (491). Imprecise language cannot spoil all knowledge; the important work of discovery will persist regardless of human imperfection. However, abuse of language can contribute to error and slow progress—and it can lead others astray. Every human struggle and controversy can trace its origins to the abuse of language.

Locke proposes four rules to help correct the problem. First, people should strive to never use words without referencing the idea they signify. Second, they should be precise. Third, they should try to use words as others best understand them. Finally, people should define or clarify when needed. Speakers can improve clarity by providing synonyms or presenting sensory experiences so that listeners may understand their meaning. In addition, speakers can use demonstration when ideas are of mixed modes and difficult to relay. Locke provides many recommendations for the use of language. He concludes by suggesting that philosophers should use the same word repeatedly when referencing the same idea.