Lewis Campbell was the first to make exhaustive use of stylometry to prove the great probability that the "Critias", "Timaeus", "Laws", "Philebus", "Sophist", and "Statesman" were all clustered together as a group, while the "Parmenides", "Phaedrus", "Republic", and "Theaetetus" belong to a separate group, which must be earlier (given Aristotle's statement in his "Politics" that the "Laws" was written after the "Republic"; cf. Diogenes Laërtius "Lives" 3.37). What is remarkable about Campbell's conclusions is that, in spite of all the stylometric studies that have been conducted since his time, perhaps the only chronological fact about Plato's works that can now be said to be "proven" by stylometry is the fact that "Critias", "Timaeus", "Laws", "Philebus", "Sophist", and "Statesman" are the latest of Plato's dialogues, the others earlier.