The Pyrrhonean believed that ideas give us no knowledge of the outer world; the Academic Sceptic believed that we cannot distinguish between true and false ideas, so such knowledge is impossible.  The Pyrrhonean denied that truth could exist in ideas because of their contradictory nature, and consequently the existence of all truth, [Greek:  meden einai te aletheia epi panton].[1] The Academic Sceptic granted that the truth was possibly contained in ideas, but affirmed that it could never be known to us.  The Pyrrhoneans prided themselves on still being seekers, for although ordinary ideas are too contradictory to give knowledge of the outer world, they did not deny that such knowledge might be possible, but simply suspended the judgment regarding it.  To the Pyrrhonean the result corresponded to the method.  All ideas thus far known revealed nothing of the truth, therefore he still sought.  The Academician tried logically to prove that the truth is impossible to find.  It is the relation of the dialectician to the empiricist, and the two varieties of Scepticism are explained by their difference in origin.  In Pyrrhonism there was no constructive element.  In the Academic Scepsis such an element was found throughout all its history in the theory of Probability.  Arcesilaus himself laid great stress upon this doctrine, which Sextus carefully shows us[2] is utterly inconsistent with Pyrrhonism.  Arcesilaus plainly teaches that, having suspended one’s judgment in regard to matters of knowledge, one should control his choices, his refusals, and his actions by the probable.[3]

    [1] Diog.  IX. 11, 61.

    [2] Hyp. I. 229.

    [3] Compare Maccoll Op. cit. 39.

After Antiochus introduced Eclecticism into the Academy, Pyrrhonism was the only representative of Greek Scepticism, and it flourished for over two centuries after our era, and then also disappeared, no more to exist as a regular philosophical school.

Having considered at length the essence of Pyrrhonism as presented by Sextus Empiricus, it now remains to briefly note the characteristics that formed its strength and weakness, and the causes of its final downfall.  Herbart says that every philosopher is a Sceptic in the beginning, but every Sceptic remains always in the beginning.  This remark may well be applied to Pyrrhonism.  We find in its teachings many fundamental philosophical truths which might have formed the beginning of great philosophical progress, but which were never developed to any positive results.  The teachings of Pyrrhonism were some of them well fitted to prepare the way to idealism.  The great idea of the relativity of Vorstellungen is made very prominent by the ten Tropes of [Greek:  epoche].  Aenesidemus, in his eight Tropes against aetiology, shows the absurdity of the doctrine of causality when upheld on materialistic grounds.  That was to him final, [Greek:  epei ouk estai aition.] He could not divine that although