[1] Zeller Op. cit. p. 25.

At the time of the separation of Pyrrhonism from the Academy, no other force was as strong in giving life to the school as the systematic treatment by Aenesidemus of the Ten Tropes of [Greek:  epoche].  The reason of this is evident.  It was not that the ideas of the Sceptical Tropes were original with Aenesidemus, but because a definite statement of belief is always a far more powerful influence than principles which are vaguely understood and accepted.  There is always, however, the danger to the Sceptic, in making a statement even of the principles of Scepticism, that the psychological result would be a dogmatic tendency of mind, as we shall see later was the case, even with Aenesidemus himself.  That the Sceptical School could not escape the accusation of dogmatizing, from the Dogmatics, even in stating the grounds of their Scepticism, we know from Diogenes.[1] To avoid this dogmatic tendency of the ten Tropes, Sextus makes the frequent assertion that he does not affirm things to be absolutely true, but states them as they appear to him, and that they may be otherwise from what he has said.[2]

    [1] Diog.  IX. 11, 102.

    [2] Hyp. I. 4, 24.

Sextus tells us that “Certain Tropes, ten in number, for producing the state of [Greek:  epoche] have been handed down from the older Sceptics."[1] He refers to them in another work as the “Tropes of Aenesidemus."[2] There is no evidence that the substance of these Tropes was changed after the time of Aenesidemus, although many of the illustrations given by Sextus must have been of a later date, added during the two centuries that elapsed between the time of Aenesidemus and Sextus.  In giving these Tropes Sextus does not claim to offer a systematic methodical classification, and closes his list of them, in their original concise form, with the remark, “We make this order ourselves."[3] The order is given differently by Diogenes, and also by Favorinus.[4] The Trope which Sextus gives as the tenth is the fifth given by Diogenes, the seventh by Sextus is the eighth given by Diogenes, the fifth by Sextus, the seventh by Diogenes, the tenth by Diogenes, the eighth by Sextus.  Diogenes says that the one he gives as the ninth Favorinus calls the eighth, and Sextus and Aenesidemus the tenth.  This statement does not correspond with the list of the Tropes which Sextus gives, proving that Diogenes took some other text than that of Sextus as his authority.[5] The difference in the order of the Tropes shows, also, that the order was not considered a matter of great importance.  There is a marked contrast in the spirit of the two presentations of the Tropes given by Sextus and Diogenes.  The former gives them not only as an orator, but as one who feels that he is defending his own cause, and the school of which he is the leader, against mortal enemies, while Diogenes relates them as an historian.

    [1] Hyp. I. 36.