A Lockean Glossary
Based on Book II and IV of
the Essay Concerning Human Understanding
Contact: Dr. Jan Garrett
Last revised date: February 27, 2004
The numerals given refer to pages (and columns) in the edition of Locke's Essay excerpted in Ariew and Watkins, eds., Modern Philosophy: An Anthology of Primary Sources (Hackett, 1998)
tabula rasa = blank slate, Locke's metaphor for the mind's condition before experience
sensation = External Perception = the power of sense-perception, a purely passive power; source of our (concrete) ideas of sense, such as our ideas of color, sound, shape, smell, etc. (276.1-2)
reflection = the operation whereby the mind turns its attention to its own operations; reflection is the source of ideas of reflection (276.2)
idea = an immediate object of perception, thought, or understanding (MP 286); all ideas are in the mind
ideas of sense = ideas that arise in sensation; we receive them passively.
ideas of reflection = ideas that arise when we reflect upon our mental operations, such as the idea of imagination, the idea of sense-perception, the idea of memory, the idea of doubting, the idea of willing, etc. (276.2)
simple ideas = ideas that give one uniform appearance, e.g., smell of a rose; whiteness of a lily (281)
simple ideas of one sense = e.g., smell of a rose (see secondary qualities)
simple ideas of two senses = e.g., shape or extension of a box, the uniform motion of some object (284); see primary qualities
complex ideas = ideas that arise from joining, relating, or abstracting from, simple ideas (293)For example, joining occurs when we have an idea of a rose including simple ideas of smell, color, shape; relating when we see that one thing's whiteness is more intense than another's; abstracting, when we create an abstract idea from simple or simpler ideas, e.g., rectangle from images of rectangles. Complex ideas include modes, substances, and relations (294). Complex ideas are actively constructed. Among them are our abstract ideas. For abstract ideas, see nominal essence, below.
simple ideas of reflection. Examples: perception, willing.
simple ideas of both sense and reflection. Examples: power, unity, existence, pleasure and pain
qualities = the power of a thing to produce an idea in the mind; includes primary, secondary, and tertiary qualities
primary qualities = qualities such as solidity, figure (shape), mobility; ideas of primary qualities, according to Locke, resemble the qualities of which they are ideas. (286.2)
secondary qualities = qualities such as yellow, loud, sweet, sour, stinky, hard, soft, etc. (286-87); ideas of secondary qualities, according to Locke contrary to naive common sense, do not resemble the qualities of which they are ideas (i.e., the powers in things that produce those ideas)
tertiary qualities = mere powers; qualities such as flexibility, ductility; and the power of sun to melt wax; according to Locke and to naive common sense, ideas of tertiary qualities do not resemble the powers in things that produce these ideas. (289) See active and passive powers.
passive power = the capacity a thing has for being changed by another thing (301), e.g., the power of wax to be melted by the sun. (We receive the idea of this power from almost all sensible things.)
active power = the capacity a thing has for changing another thing. (301)From bodies we receive at best an obscure idea of active power; the best source of our notion of active power is reflection on our will.
modes = complex ideas that "do not contain in them the supposition of [things?] subsisting by themselves," e.g., triangle, gratitude, murder (294.2) That is, in entertaining [ideas of] modes we do not suppose that they exist by themselves, but rather in some substance.
simple modes = ideas that are complex in a repetitive way, such as ideas of space and time. Ideas of length involve the repetition of, say, inches or miles; ideas of time involve repetition of similar units, e.g., minutes (in an hour), hours (in a day), etc.
mixed modes = modes (complex ideas distinct from complex ideas of substances) that are not simple modes and made up of scattered and independent ideas put together by the mind, such as obligation, drunkenness, a lie, sacrilege, murder.The nouns ("names") assigned to these mixed modes help us hold the component ideas together. (310) Mixed modes are crucial in ethics, theology, jurisprudence, etc. (312)
ideas of (single) substances = combinations of simple ideas as are taken to represent distinct particular things subsisting by themselves (294.2)Powers make up a large part of our complex ideas of substance (314). "Our specific ideas of substances are nothing else but a collection of a . . . number of simple ideas, considered as united in one thing" (316)
relation = complex idea that consists in consideration and comparing of one idea with another (295.1)
the will = the power of the mind to order consideration of any idea, or the forebearing to consider it; or to prefer the motion of any party of the body to its rest . . . (302)
the understanding = the mind's power of perception: perception of ideas in our minds; perception of the signification of signs; perception of the connection or repugnance, agreement or disagreement, . . . between any of our ideas. (302-303)
volition = the actual exercise of the will; the mental act of preferring one course of action to another (302); acts performed as a result of a volition are "voluntary," those performed without a volition are "involuntary"
liberty = a power in any agent to do or refrain [from] any particular action according to the determination or thought of his mind by which either of them is preferred to the other (303); where either of them is not in the agent's power to produce according to volition, that agent is not at liberty but under necessity. (303)
idea of immaterial spirit = complex idea formed by joining the ideas of our mental operations considered as subsisting in some substance; thinking and motivity are the primary ideas of spirit (317)
abstract idea = the nominal essences of species and genera (332); see below.
adequate idea = an idea that "perfectly represent[s] the archetype [original] which the mind supposes [it] taken from; which it intends [the idea] to stand for, and to which it refers [the idea]" (Book II, chap. 31, section 1; not in MP) (Locke says that our ideas of primary and secondary qualities are adequate.)
inadquate idea = an idea that incompletely represents the original to which it is referred (Locke says that our ideas of substance are inadequate.)
real essence = the very being of anything; the real internal, but generally in substances unknown constitution of things on which their discoverable qualities depend (333)
nominal essence = the combination of ideas we use to reliably sort things into a particular class; correspond to our abstract ideas of things, especially material substance; e.g., man as an erect, speaking, mammal; horse as a quadruped mammal with a mane, gold as a solid, yellow, malleable, fusible [stuff]. (333-335)
knowledge = an activity of the human mind, grasping the agreement or disagreement of our ideas; sometimes concerns sameness or difference; sometimes relation; sometimes necessary connection, sometimes existence. (339.1)
intuitive knowledge = direct perception of the agreement or disagreement of two ideas without help of any other, the "first degree" of knowledge; deals with truths that cannot conceivably be false. (341.2-342.1)
demonstrative knowledge = perception of the agreement or disagreement of two ideas with the help of intermediate ideas; the "second degree" of knowledge; deals with truths that cannot conceivably be false. (344.1)
sensitive knowledge = "a perception of the particular existence of finite beings outside us" (344.1); "third degree" of knowledge; it is less certain than intuitive and demonstrative knowledge. (349.1)
judgment = the capacity the mind uses when it "takes its ideas . . . to be true, or false, without perceiving a demonstrative evidence in the proofs"; the act of putting ideas together in the mind, or separating them in the mind, when their agreement or disagreement is not perceived to be certain but only presumed to be so. (not in MP)Judgment is closely associated with "probability" as Locke understands it. Faith is a type of judgment.
right judgment = the mental act of uniting or separating ideas as things really are, without perceiving the link as certain (Book IV, chapter 14, section 4; not in MP).
assent to an idea = receive the idea as true.
probability = (368.2) likeliness to be true; in Locke it is the contrary of certainty; relates to statements about which "we have no certainty but only some inducements" to regard them as true (368.2).
assurance = the highest degree of probability; seems to concern general judgements, widely supported by witnesses, about how material things interact: for example, fire warms a person, iron sinks in water. (370.2)
confidence = the second highest degree of probability, which attaches to judgments concerning a particular when it is witnessed by others and the judgements are consistent with general judgments about what is usually true. (371.1)
faith = "nothing but a firm Assent of the Mind: which if it be regulated, as is our Duty, cannot be afforded to anything but upon good Reason; and so cannot be opposite to it" (Book IV, chap. 17, sect. 24, not in MP)Locke elsewhere defines faith in terms of revelation from God and says that it is "a settled and sure principle of assent and assurance, and leaves no manner of room for doubt or hesitation," but only providing that there is good evidence that it does come from God. (373)
reason = the discovery of the certainty or probability of such propositions or truths which the mind arrives at by deductions [inferences] made from such ideas which it has got by . . . sensation and reflection (Book IV, chap. 18, sect. 2, not in MP).
original revelation = "that first impression, which is made immediately by God, on the mind of any man." (not in MP)
traditional revelation = "those impressions delivered over to others in words and the ordinary ways of conveying our conceptions one to another" (chap. 18, sect. 3, not in MP)