It is always difficult to determine when an institution begins a process of decline, and philosophical institutions are no exception to this rule. What one can say, in the case of the Academy, is that the exceptionally long and brilliant scholarchate of Carneades - he was head of the school for several decades before leaving voluntarily in 137 BCE - marked the high point of the sceptical Academy, while at the same time revealing the fault-lines that would lead to its division, and then to its disappearance. There are several reasons for this two-sided legacy.

(a) Like his predecessor Arcesilaus, Carneades had not himself written any philosophical work. Oral teaching lends itself more than any other to contradictory interpretations. Carneades had a disciple, Zeno of Alexandria, who took notes during his courses, notes in which the master could at no time recognize his own thinking. One may imagine that what was true for Zeno (in some sense Carneades' secretary) was all the more so for his other students, whose divergent notes must have given rise to disputes. It is not impossible that Carneades himself had incited a certain rivalry among his followers, like that which Cicero reports in Orator 51: he used to say that Clitomachus said the same things as him, but that Charmadas said them in the same way as he did.