As there is a condition of mind which is characterized by invincible ignorance, so there is another which may be said to be possessed of invincible knowledge; and it would be paradoxical in me to deny to such a mental state the highest quality of religious faith,—I mean certitude. (J. H. Newman, Grammar of Assent, 138–139)

‘She's an artist. She keeps saying the same thing without repeating herself. (Iris Murdoch, The Good Apprentice, 66)

In being initiated into our life as human beings we are subject to causal influences; guiding, teaching, restraint, compulsion, incentives, rewards, warnings, penalties. Until such influences have achieved their most important work we do not share the human understanding within which there can be ratiocination, evidence, argument. So there is and must be a causal story of how we come to acquire a human understanding; a causal story for the species as a whole and a causal story for each of us; and there is not and could not be any acceptable account, either for the species or for the individual, of how we reasoned or argued our way into our initial and fundamental understanding. I say the same thing without repeating myself if I call such knowledge and understanding invincible. It is not possible to Overthrow it by reasoning any more than it is possible to establish it by reasoning.