G.K. Chesterton, St. Thomas Aquinas

At the top of his fury, Thomas Aquinas understands, what so many defenders of orthodoxy will not understand. It is no good to tell an atheist that he is an atheist; or to charge a denier of immortality with the infamy of denying it; or to imagine that one can force an opponent to admit he is wrong, by proving that he is wrong on somebody else's principles, but not on his own. After the great example of St. Thomas, the principle stands, or ought always to have stood established; that we must either not argue with a man at all, or we must argue on his grounds and not ours.

[Chapter III, "The Aristotelian Revolution"]

Victor Hugo, Les Miserables

With nihilism no discussion is possible. For the logical nihilist doubts the existence of his interlocutor, and is not quite sure that he exists himself.

From his point of view it is possible that he may be to himself only a "conception of his mind."
However, he does not perceive that all he has denied he admits in a a mass by merely pronouncing the word "mind."

To sum up, no path is left open for thought by a philosophy that makes everything come to but one conclusion, the monosyllable "No."

To "No," there is but one reply: "Yes."

Nihilism has no scope. There is no nothing. Zero does not exist. Everything is something. Nothing is nothing.

Man lives by affirmation even more than he does by bread.

["Cosette," Book the Seventh, Chapter VI]

Victor Hugo, Les Miserables

There is, we are aware, a philosophy that denies the infinite. There is also a philosophy classed pathologically, which denies the sun; this philosophy is called blindness.

["Cosette," Book the Seventh, Chapter VI]

C.S. Lewis, Mere Christianity

When I was an atheist I had to try to persuade myself that most of the human race have always been wrong about the question that mattered to them most; when I became a Christian I was able to take a more liberal view.

[Book II, Chapter 1, "The Rival Conceptions of God"]