Sextus claims that there are three fundamental grounds of difference between Pyrrhonism and the Academy.  The first is the doctrine of probability which the Academicians accept in regard to the superior trustworthiness of some ideas over others.[2] The second is the different way in which the two schools follow their teachers.  The Pyrrhoneans follow without striving or strong effort, or even strong inclination, as a child follows his teacher, while the Academicians follow with sympathy and assent, as Carneades and Clitomachus affirm.[3] The third difference is in the aim, for the Academicians follow what is probable in life.  The Sceptics follow nothing, but live according to laws, customs, and natural feelings undogmatically.[4]

The difference between the later teaching of the Academy and Pyrrhonism is evident, and Sextus treats of it briefly, as not requiring discussion,[5] as Philo taught that the nature of facts is incomprehensible, and Antiochus transferred the Stoa to the Academy.  It is therefore evident, from the comparison which we have made, that we do not find in the Academy, with which Scepticism after the death of Timon was so long united, the exact continuance of Pyrrhonism.  The philosophical enmity of the two contemporaries, Timon and Arcesilaus, the Academician who had most in common with Pyrrhonism, is an expression of the fundamental incompatibility between the two schools.

    [1] Hyp.  I. 227.

    [2] Hyp.  I. 229.

    [3] Hyp.  I. 230.

    [4] Hyp.  I. 231.

    [5] Hyp.  I. 235.

During all the chequered history of the Academy the dormant idealism was there, underlying the outward development.  Although during the time of Arcesilaus and Carneades the difference was so slight as to seem a mere matter of form of expression, yet the different foundations on which the two schools stood was always recognisable.  On the one hand there was the germ of idealism which was destined to awake to a new life, and on the other, the attempt at absolute negation which was to result in the final extinction of Pyrrhonism.  We find in both, it is true, especially in the time of Arcesilaus, the aim of [Greek:  epoche].[1] Both placed great weight on [Greek:  isostheneia], or the equal value of opposing arguments.[2] The foundation of the [Greek:  epoche] was, however, different in the two cases.  Arcesilaus founded his on dialectic, while Pyrrho’s was empirical.

    [1] Hyp. I. 232.

    [2] Diog.  IX. 73; Hyp. II. 130; III. 65.