Philosophy 100 Essential Thinkers

by Philip Stokes

Among Locke’s simple ideas is a distinction between those that are primary qualities of objects and others that are secondary qualities. The distinction divides those qualities thought to be essential and inherent to all objects and those that are apparent only on account of the effect objects have on our senses. Primary qualities are those such as solidity, extension, shape, motion or rest, and number. Secondary qualities are those such as colour, scent and taste. These are secondary because, according to Locke, they do not inhere in objects themselves, but are causally produced only in our minds by the effect of an object’s primary qualities upon our senses. Another way of conceiving them is to say primary qualities are objective (really exist) and secondary ones subjective (only exist in the minds of observers). In the popular conundrum of whether a falling tree makes a sound when there is no one to hear it, Locke’s view would be that the falling tree creates vibrations in the air, but that there is no ‘sound’ strictly speaking, since sound is not a ‘real’ or primary quality.