He further questioned, and successfully, the authorship of the Creed attributed {50} to the Apostles, the authenticity of the writings of Dionysius the Areopagite and of the letter of Christ to King Abgarus, preserved and credited by Eusebius.
[Sidenote: Attack on Christian ethics] His attack on Christian ethics was still more fundamental.

In his _Dialogue on Free Will_ he tried with ingenuity to reconcile the freedom of the will, denied by Augustine, with the foreknowledge of God, which he did not feel strong enough to dispute.

In his work on _The Monastic Life_ he denied all value to asceticism.

Others had mocked the monks for not living up to their professions; he asserted that the ideal itself was mistaken.

But it is the treatise _On Pleasure_ that goes the farthest.