... There are five ideas that ripen here and now in two ways. What five? Faith, preference, hearsay-learning, arguing upon evidence, and liking through pondering a view. Now something may have faith well placed in it and yet be hollow, empty, and false; and again something may have no faith placed in it and yet be factual, true, and no other than it seems; and so with preference and the rest. If a man has faith, then he guards truth when he says, "My faith is thus," but on that account draws no unreserved conclusion, "Only this is true, the other is wrong." In this way he guards the truth; but there is as yet no discovery of truth. And so with preference and the rest.
How is truth discovered? Here a bhikkhu lives near some village or town. Then a householder or his son goes to him in order to test him in three kinds of ideas, in ideas provocative of greed, of hate, and of delusion, wondering, "Are there in this venerable one any such ideas, whereby his mind being obsessed he might not knowing, say 'I know,' unseeing, say 'I see,' or to get others to do likewise, which would be long for their harm and suffering?" While thus testing him he comes to find that there are no such ideas in him, and he finds that, "The bodily and verbal behavior of that venerable one are not those of one affected by lust or hate or delusion. But the True Idea that this venerable one teaches is profound, hard to see and discover; yet it is the most peaceful and superior of all, out of reach of logical ratiocination, subtle, for the wise to experience; such a True Idea cannot be taught by one affected by lust or hate or delusion."
It is as soon as by testing him, he comes to see that he is purified from ideas provocative of lust, hate, and delusion, that he then plants his faith in him. When he visits him he respects him, when he respects him he gives ear, one who gives ear hears the True Idea, he remembers it, he investigates the meaning of the ideas remembered. When he does that he acquires a preference by pondering the ideas. That produces interest. One interested is actively committed. So committed he makes a judgment. According to his judgment he exerts himself. When he exerts himself he comes to realize with the body the ultimate truth, and he sees it by the penetrating of it with understanding. That is how there is discovery of truth. But there is as yet no final arrival at truth. How is truth finally arrived at? Final arrival at truth is the repetition, the keeping in being, the development, of those same ideas. That is how there is final arrival at truth."