William Kingdon Clifford, answered from the texts and cited to the page.
A shipowner is about to send an emigrant vessel to sea. He knows she is old, imperfectly built, and in want of repairs; doubts have been suggested to him about her seaworthiness. He suppresses those doubts, tells himself she has weathered storms before, puts his trust in Providence, and acquires a sincere and comfortable conviction that all is well.1
She goes down in mid-ocean. What shall we say of him? That he was guilty of the death of those men — not because his belief was false, but because he had no right to believe on such evidence as was before him.2 He had not earned the belief by honest inquiry; he had stolen it by stifling his doubts. That is evidentialism, stated in its proper form.
Not a slogan but a verdict on a case: the wrong lies in the manner of acquiring the belief, entirely independent of whether the belief happens to be true. Suppose the ship had arrived safely — the shipowner would be no less guilty, only luckier.3 The guilt is in the process, not the outcome. Now, a common misreading must be cleared away at once.
The principle is not that a man must personally verify everything he believes. Two-thirds of what I wrote on this subject concerns the legitimate weight of authority — when we may rightly trust the testimony of others, and on what conditions.4 No one has tested a hundredth part of the knowledge he relies on by immediate observation, and it would be absurd to demand it.5
What is demanded is that the habit of inquiry be kept alive: that a man not work himself, knowingly and willingly, into a frame of mind that forecloses the question.6 The self-referential challenge — what is the evidence for the evidentialist principle itself? — I take seriously, and I address it in the third part of the essay. The principle is not a report of a discovered fact; it is a rule of conduct, and rules of conduct are established by their consequences to the common life.
Those who have most nearly done their duty in this respect have found that the great practical principles — about right and wrong in society, about the physical world we must navigate — stand out more clearly the more honestly they are tested, and never suffer from investigation.7 The beliefs that are propped up against inquiry are precisely the ones we should distrust.
One further thing. It is sometimes said that the objection to believing without evidence is really an objection to action on such belief, and that the belief itself might be excused. I grant that the distinction has some use — a man fixed in a conviction still has a choice about what he does, and cannot escape the duty of investigating on the strength of his convictions.8
But the separation cannot be made complete. No man holding a strong belief on one side of a question can investigate it with the fairness he would bring to it were he genuinely in doubt; the unfounded belief unfits him for the very duty of inquiry that might correct it.9 Belief and action are not two compartments; the one flows into the other, and the corruption of the one corrupts the other.
He said to himself that she had gone safely through so many voyages and weathered so many storms that it was idle to suppose she would not come safely home from this trip also... In such ways he acquired a sincere and comfortable conviction that his vessel was thoroughly safe and seaworthy.The Scientific Basis of Morals and Other Essays, incl. The Ethics of Belief
he was verily guilty of the death of those men. It is admitted that he did sincerely believe in the soundness of his ship; but the sincerity of his conviction can in no wise help him, because he had no right to believe on such evidence as was before him.The Scientific Basis of Morals and Other Essays, incl. The Ethics of Belief
He had acquired his belief not by honestly earning it in patient investigation, but by stifling his doubts. And although in the end he may have felt so sure about it that he could not think otherwise, yet inasmuch as he had knowingly and willingly worked himself into that frame of mind, he must be held responsible for it.The Scientific Basis of Morals and Other Essays, incl. The Ethics of Belief
Are we then to become universal skeptics, doubting everything, afraid always to put one foot before the other until we have personally tested the firmness of the road?The Scientific Basis of Morals and Other Essays, incl. The Ethics of Belief
Are we to deprive ourselves of the help and guidance of that vast body of knowledge which is daily growing upon the world, because neither we nor any other one person can possibly test a hundredth part of it by immediate experiment or observation?The Scientific Basis of Morals and Other Essays, incl. The Ethics of Belief
Inquiry into the evidence of a doctrine is not to be made once for all, and then taken as finally settled. It is never lawful to stifle a doubt.The Scientific Basis of Morals and Other Essays, incl. The Ethics of Belief
Those men who have most nearly done their duty in this respect have found that certain great principles, and these most fitted for the guidance of life, have stood out more and more clearly in proportion to the care and honesty with which they were tested... The beliefs about right and wrong which guide our actions in dealing with men in society, and the beliefs about physical nature which guide our actions in dealing with animate and inanimate bodies, these never suffer from investigation.Lectures and Essays Vol II, ed. Pollock
even when a man's belief is so fixed that he cannot think otherwise, he still has a choice in regard to the action suggested by it, and so cannot escape the duty of investigating on the ground of the strength of his convictions.The Scientific Basis of Morals and Other Essays, incl. The Ethics of Belief
No man holding a strong belief on one side of a question, or even wishing to hold a belief on one side, can investigate it with such fairness and completeness as if he were really in doubt and unbiassed; so that the existence of a belief not founded on fair inquiry unfits a man for the performance of this necessary duty.Lectures and Essays Vol II, ed. Pollock