Democritus · Philosophy
Democritus’ epochal distinction between the qualities things really have (the shapes and motions of atoms) and the qualities they only seem to have (colour, taste, warmth) - which exist not in the world but in us, ‘by convention.’
Democritus’ atomism forced upon him one of the most important discoveries in the history of philosophy: that there is a deep gap between the world as it really is and the world as it appears to us. If reality is, at bottom, nothing but colourless, tasteless atoms moving in the void, then where do all the colours, flavours, sounds, smells, and warmth of our experience come from? They cannot be in the atoms, for the atoms have only shape, size, and motion. And yet they are undeniably there in our experience: the apple really does look red and taste sweet. Democritus’ solution was to distinguish two radically different kinds of quality, and to assign them to two different places.
On one side are the qualities that belong to the atoms themselves, ‘in reality’ (Greek eteê, ‘in truth’): shape, size, arrangement, position, and motion. These are objective, mind-independent features of the world; they would be exactly what they are whether or not anyone perceived them. On the other side are the qualities that exist only ‘by convention’ (nomôi, ‘by custom’ or ‘by usage’): colour, taste, smell, sound, hot and cold. These are not in the atoms; they arise only when atoms strike a perceiving body and produce a sensation. Remove the perceiver, and the red and the sweet vanish, leaving only the colourless atoms that were always the whole of the external truth.
Democritus did not leave the origin of sensory qualities mysterious; he gave detailed, ingenious mechanical explanations, deriving each quality from the shapes and motions of the atoms involved. Taste, for instance, he traced to the shapes of the atoms striking the tongue. Sweet things, he held, are composed of atoms that are smooth and round, which is why they glide soothingly over the tongue; sour and bitter things are made of atoms that are angular, jagged, and hooked, which tear and rasp at the tongue and so produce the sharp, unpleasant sensation. Salty tastes come from large, jagged atoms; pungent tastes from sharp, angular, twisted ones. The sensation, in each case, is the felt effect of a particular atomic shape on the sense-organ.
This is the opening of the lesson. The rest — the dialogue, the primary source, and the recall — is in the app.
You learned that Democritus distinguished the qualities atoms really have (shape, size, arrangement, motion) from the qualities that exist only ‘by convention’ in our experience (colour, taste, smell, warmth), which arise from how atoms strike our senses. Explain this distinction in your own words.
Leads to John Locke.
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