As an example of this method, Plato uses the essence of ‘even’ (as opposed to ‘odd’): ‘Number … may be a thing capable of division into equal parts. If it is so divisible, number is named “even”; and the definition of the name “even” is “a number divisible into equal parts”… And when we are given the name and asked about the definition, or when we are given the definition and asked about the name, we speak, in both cases, of one and the same essence, whether we call it now “even” or “a number divisible into equal parts”.’
