Aristocles also attributes them.[3] They are not mentioned in
Diogenes' life of Timon, the immediate disciple of Pyrrho.
Cicero has no knowledge of them, and does not refer to them in
his discussion of Scepticism.

[1] Compare Saisset _Op. cit._ p. 78.

[2] Brochard _Op. cit._ 254, Note 4.

[3] Aristocles _Eus. praep. ev._ XIV. 18. 8.

Aenesidemus was undoubtedly the first to formulate these Tropes,
but many things tend to show that they resulted, in reality,
from the gradual classification of the results of the teachings
of Pyrrho, in the subsequent development of thought from his own
time to that of Aenesidemus. The ideas contained in the Tropes
were not original with Aenesidemus, but are more closely
connected with the thought of earlier times. The decidedly
empirical character of the Tropes proves this connection, for
the eight Tropes of Aetiology, which were original with
Aenesidemus, bear a far stronger dialectic stamp, thus showing a
more decided dialectic influence of the Academy than is found in
the Tropes of [Greek: epochê]. Many of the illustrations given
of the Tropes also, testify to a time of greater antiquity than
that of Aenesidemus. The name Trope was well known in ancient
times, and the number ten reminds us of the ten opposing
principles of Pythagoras, and the ten categories of Aristotle,
the fourth of which was the same as the eighth Trope. The
terminology, however, with very few exceptions, points to a
later period than that of Pyrrho. Zeller points out a number of