“In order to conceive, and to steep ourselves in, unreality, we must have it constantly present to our minds. The day we feel it, see it, everything becomes unreal, except that unreality which alone makes existence tolerable.”

Source: 1910s, Introduction to Mathematical Philosophy (1919), Ch. 16: Descriptions

Abide as the Self

Epistulae Morales ad Lucilium (Moral Letters to Lucilius), Letter LVIII: On Being

Anathemas and Admirations (1987)

Song lyrics, Discovery (1984)

On Truth and Lie in an Extra-Moral Sense (1873)
Context: The liar is a person who uses the valid designations, the words, in order to make something which is unreal appear to be real. He says, for example, "I am rich," when the proper designation for his condition would be "poor." He misuses fixed conventions by means of arbitrary substitutions or even reversals of names. If he does this in a selfish and moreover harmful manner, society will cease to trust him and will thereby exclude him. What men avoid by excluding the liar is not so much being defrauded as it is being harmed by means of fraud. Thus, even at this stage, what they hate is basically not deception itself, but rather the unpleasant, hated consequences of certain sorts of deception. It is in a similarly restricted sense that man now wants nothing but truth: he desires the pleasant, life-preserving consequences of truth. He is indifferent toward pure knowledge which has no consequences; toward those truths which are possibly harmful and destructive he is even hostilely inclined.

Source: Sundays at Tiffany's

All Gall Is Divided (1952)

Raised by Wolves, season 1, episode 1. Mother.