dealism. 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 the result which he presented was logical, it only led
to a higher truth. It was reserved for the greatest of modern
philosophers to reveal to the world that causality is a
condition, and a necessary condition, of thought. When
Aenesidemus proved by his seventh Trope that causality is
subjective, he regarded it as fatal to the doctrine; yet this
conclusion was a marked step in advance in critical philosophy,
although Aenesidemus could not himself see it in all its
bearings. The great difference between Aenesidemus and Kant is
the difference between the materialist and the believer in
subjective reality. Both agreed in the unknown nature of the
_Ding an sich_, but this was to the Pyrrhonist the end of all
his philosophy; to Kant, however, the beginning.

Pyrrhonism has rendered, notwithstanding its points of fatal
weakness, marked service to the world in science, philosophy,
ethics, and religion. It quickened scientific thought by
emphasising empirical methods of investigation, and by
criticising all results founded without sufficient data upon
false hypotheses. If, instead of denying the possibility of all
science because of the want of a criterion of the truth of
phenomena, the Pyrrhonists had comprehended the possibility of a
science of phenomena, they might have led the world in
scientific progress.[1] Their service to philosophy lay in the
stimulus to thought that their frequent attacks on dogmatic
beliefs occasioned. Pyrrhonism brought together all the most
prominent theories of the old schools of philosophy to test
their weakness and expose their contradictions, and this very
process of criticism often demonstrated the power of the truth
which they contained.

Sextus Empiricus was often charged by the Church Fathers with
corrupting religious belief, and yet the greatest service which
Pyrrhonism has rendered the world was in religious and ethical
lines. This service did not, naturally, consist in destroying
belief in absolute truth, as the Sceptic professed to do, but in
preparing the way to find it. The bold attacks of Scepticism on
all truth led men to investigate