On Understanding a General Name

One venerable, and supposedly thoroughly discredited, way of thinking about general names is to conceive of them as names of essences. This is not as transparently foolish a conceit as is nowadays generally supposed. Locke used the term ‘essence’ in two related senses; first, as ‘the being of any thing whereby it is what it is’, and second, as a name for any principle or procedure (for example, matching against an abstract idea) which enables us to rank things under ‘sortal names’ (general names) (Locke, 1690, 3.2.15). In this latter sense, knowing the essence which corresponds to horse or lead, for example is, according to Locke, knowing ‘what are the alterations may or may not be in a horse or lead, without making either of them to be of another species’ (Locke, 1690, 3·3·13).