EN
This study investigates Plato's so-called theory of ideas. The starting point of the investigation is an analysis of the first part of the 'Parmenides', where Parmenides presents a broad and thorough criticism of ideas. This analysis shows, firstly, that the usual rendering of the Greek terms 'eidos' and 'idea' as 'Idea' (in a metaphysical or Platonic way) is misleading and that it is more appropriate to render these Greek terms using the phrases 'characteristic kind' or 'generic nature'. In the course of a short excursion into the middle dialogues it is shown that Plato's 'theory of ideas' - that is, Socrates' conception of independent 'Eide' which Parmenides criticises in the dialogue of the same name - has two sources. (1) In the early dialogues the terms 'eidos' and 'idea' denoted the characteristic features common to a group of things - in particular, virtues. (2) In the middle dialogues 'ideas' were conceived above all as objects of knowledge (cf. the doctrine of reminiscence), which accounts for the use of substantialising adjectives and for the qualifier 'in itself' (cf. auto to kalon).