The argument from the relatives in 'Peri ideon'

This paper examines the argument from the relatives taken from Alexander of Aphrodisias' text which is traditionally ascribed to Aristotle under the t itle "Peri ideon". The analysis of the passage and a brief discussion of Ar istotle's criticism of this argument is presented, trying to show that Plat o is forced to produce ideas also for relatives and for that reason the arg ument fails, since as Aristotle believes we cannot postulate the relatives as a class of things existing by themselves (Metaph. 990b 15-17)