Assent-Dissent

No man can sit down and withhold his hands from the warfare against wrong and get peace from his acquiescence. (Woodrow Wilson)

In formal logic, a contradiction is the signal of a defeat: but in the evolution of real knowledge it marks the first step in reason for the utmost toleration of variety of opinion. (Alfred North Whitehead)

Dissension, well directed, may divide even the true-hearted, as a mighty stream of waters divides mountains of solid rock. (Panchatantra)