Many simple modes—especially very fine degrees of the same simple idea—have no distinct names and ar… — John Locke

Many simple modes—especially very fine degrees of the same simple idea—have no distinct names and are little noticed, either because we lack precise measures to distinguish them or because such refined discriminations are of no general or necessary use; nevertheless, all simple ideas still enter only by sensation and reflection, and the mind can repeat and compound them into new complex ideas.

By John Locke, from An Essay Concerning Human Understanding

Key Arguments

Locke observes that 'those simple modes which are considered but as different degrees of the same simple idea, though they are in themselves many of them very distinct ideas, yet have ordinarily no distinct names, nor are much taken notice of, as distinct ideas, where the difference is but very small between them.'
He suggests two possible explanations: 'Whether men have neglected these modes, and given no names to them, as wanting measures nicely to distinguish them; or because, when they were so distinguished, that knowledge would not be of general or necessary use, I leave it to the thoughts of others.'
He reaffirms his general empiricist thesis: 'It is sufficient to my purpose to show, that all our simple ideas come to our minds only by sensation and reflection; and that when the mind has them, it can variously repeat and compound them, and so make new complex ideas.'
He contrasts simple ideas like 'white, red, or sweet, &c.'—which 'have not been modified, or made into complex ideas, by several combinations, so as to be named'—with others such as 'unity, duration, and motion, &c., above instanced in, as also power and thinking', which 'have been thus modified to a great variety of complex ideas, with names belonging to them', reinforcing that differential naming depends on how far modes have actually been socially developed.

Source Quotes

Some simple modes have no names. In general it may be observed, that those simple modes which are considered but as different degrees of the same simple idea, though they are in themselves many of them very distinct ideas, yet have ordinarily no distinct names, nor are much taken notice of, as distinct ideas, where the difference is but very small between them. Whether men have neglected these modes, and given no names to them, as wanting measures nicely to distinguish them; or because, when they were so distinguished, that knowledge would not be of general or necessary use, I leave it to the thoughts of others.

In general it may be observed, that those simple modes which are considered but as different degrees of the same simple idea, though they are in themselves many of them very distinct ideas, yet have ordinarily no distinct names, nor are much taken notice of, as distinct ideas, where the difference is but very small between them. Whether men have neglected these modes, and given no names to them, as wanting measures nicely to distinguish them; or because, when they were so distinguished, that knowledge would not be of general or necessary use, I leave it to the thoughts of others. It is sufficient to my purpose to show, that all our simple ideas come to our minds only by sensation and reflection; and that when the mind has them, it can variously repeat and compound them, and so make new complex ideas.

Whether men have neglected these modes, and given no names to them, as wanting measures nicely to distinguish them; or because, when they were so distinguished, that knowledge would not be of general or necessary use, I leave it to the thoughts of others. It is sufficient to my purpose to show, that all our simple ideas come to our minds only by sensation and reflection; and that when the mind has them, it can variously repeat and compound them, and so make new complex ideas. But, though white, red, or sweet, &c. have not been modified, or made into complex ideas, by several combinations, so as to be named, and thereby ranked into species; yet some others of the simple ideas, viz. those of unity, duration, and motion, &c., above instanced in, as also power and thinking, have been thus modified to a great variety of complex ideas, with names belonging to them.

It is sufficient to my purpose to show, that all our simple ideas come to our minds only by sensation and reflection; and that when the mind has them, it can variously repeat and compound them, and so make new complex ideas. But, though white, red, or sweet, &c. have not been modified, or made into complex ideas, by several combinations, so as to be named, and thereby ranked into species; yet some others of the simple ideas, viz. those of unity, duration, and motion, &c., above instanced in, as also power and thinking, have been thus modified to a great variety of complex ideas, with names belonging to them. 7.

Key Concepts

those simple modes which are considered but as different degrees of the same simple idea, though they are in themselves many of them very distinct ideas, yet have ordinarily no distinct names, nor are much taken notice of, as distinct ideas, where the difference is but very small between them
as wanting measures nicely to distinguish them; or because, when they were so distinguished, that knowledge would not be of general or necessary use
all our simple ideas come to our minds only by sensation and reflection; and that when the mind has them, it can variously repeat and compound them, and so make new complex ideas
white, red, or sweet, &c. have not been modified, or made into complex ideas, by several combinations, so as to be named
yet some others of the simple ideas, viz. those of unity, duration, and motion, &c., above instanced in, as also power and thinking, have been thus modified to a great variety of complex ideas, with names belonging to them

Context

Book II, chapter XVIII, section 6, where Locke generalizes about unnamed simple modes, offers possible reasons for this, and ties the point back to his overall account of the origin and compounding of ideas.