Complex sentence: Theaetetus is a young student of mathematics who proposed three definitions that are refuted by Socrates, according to whom, knowledge cannot be defined as a perception, nor as a true opinion, nor as an explanation besides a true opinion.
Split into simpler sentences: Theaetetus is a young student of mathematics who proposed three definitions that are refuted by Socrates. Knowledge cannot be defined as a perception nor as a true opinion nor as an explanation besides a true opinion.