The system of Heraclitus offers a solution, and he accepts it. Contradictory predicates produce equilibrium in the soul because they are an expression of reality. [1] Brochard _Op. cit._ 272. As a Sceptic he claims that knowledge is impossible, and he does not find that the statement of Heraclitus disproves this, but rather that it supports his theory. He had denied the existence of science. He still does so, but now he knows why he denies it. Brochard asks why it is any more impossible that Aenesidemus should have been a follower of Heraclitus than that Protagoras was so, as Protagoras was after all a Sceptic. In conclusion, Brochard claims that the dogmatic theories attributed to Aenesidemus relate to the doctrine of the truth of contradictory predicates, which seemed to him a logical explanation of the foundation theories of Scepticism. It is right to call him a Sceptic, for he was so, and that sincerely; and he deserves his rank as one of the chiefs of the Sceptical School. Coming now to the opinion of Zeller,[1] we find that he advocates a misconception of Aenesidemus on the part of Sextus. The whole difficulty is removed, Zeller thinks, by the simple fact that Sextus had not understood Aenesidemus; and as Tertullian and Sextus agree in this misconception of the views of Aenesidemus, they must have been misled by consulting a common author in regard to Aenesidemus, who confused what Aenesidemus said of Heraclitus with his own opinion. Zeller maintains that the expression so often repeated by Sextus--[Greek: Ainesidemos kath' Herakleiton]--shows that some one of Aenesidemus' books contained a report of Heraclitus' doctrines, as Aenesidemus was in the habit of quoting as many authorities as possible to sustain his Scepticism. To justify his quotations from Heraclitus, he had possibly given a short abstract of Heraclitus' teachings; and the misconception advocated by Zeller and found both in Tertullian and Sextus, refers rather to the spirit than to the words quoted from Aenesidemus, and is a misconception due to some earlier author, who had given a false impression of the meaning of Aenesidemus in quoting what Aenesidemus wrote about Heraclitus. That is to say, Heraclitus was classed by Aenesidemus only among those who prepared the way for Scepticism, just as Diogenes[2] mentions many philosophers in that way; and that Soranus[3] and Sextus both had the same misunderstanding can only be explained by a mistake on the part of the authority whom they consulted. [1] Zeller _Op. cit._ III, pp. 31-35; _Grundriss der Geschichte der Griechischen Phil._ p. 263. [2] Diog. Laert. IX. 11, 71-74. [3] Tertullian.