Some people speak as if we were not justified in rejecting a theological doctrine unless we can prove it false. But the burden of proof does not lie upon the rejecter. I remember a conversation in which, when some disrespectful remark was made about hell, a loyal friend of that establishment said triumphantly, "But, absurd as it may seem, you cannot disprove it." If you were told that in a certain planet revolving around Sirius there is a race of donkeys who speak the English language and spend their time in discussing eugenics, you could not disprove the statement, but would it, on that account, have any claim to be believed? Some minds would be prepared to accept it, if it were reiterated often enough, through the potent force of suggestion.

I wish to propose for the reader's favourable consideration a doctrine which may, I fear, appear wildly paradoxical and subversive. The doctrine in question is this: that it is undesirable to believe a proposition when there is no ground whatever for supposing it true.

If I find some reason for doubt in each of my beliefs, that will be enough to reject all of them.

If a theory claims to be able to explain some phenomenon, but does not generate even an attempt at an explanation, then it should be banished.

Pity the theory which sets itself in opposition to the mind! It cannot repair this contradiction by any humility, and the humbler it is so much the sooner will ridicule and contempt drive it from real life.

You have no proof of this," I said.
"No. But a theory must be tested to be disproved, Mr Bastable.

I wish to propose a doctrine which may, I fear, appear wildly paradoxical and subversive. The doctrine in question is this: that it is undesirable to believe a proposition when there is no ground whatever for supposing it true. I must, of course, admit that if such an opinion became common it would completely transform our social life and our political system; since both are at present faultless, this must weigh against it.

Refusal to believe until proof is given is a rational position; denial of all outside of our own limited experience is absurd.

is hearsay upon hearsay, and I do not choose to rest my belief upon such evidence.

...no one believes an hypothesis except its originator but everyone believes an experiment except the experimenter.

I distrust every idea that doesn't seem obsolete and grotesque to my contemporaries.

But failure to disprove something is not a good reason to believe it.

[I]t is largely because I find all exercises of power by some over others—even with what passes for the latter's consent—are and must remain deeply problematic, that I find all legitimating theories not simply amusing in their pretensions but... as dangerous as they are convincing.

Each new ontological theory, propounded in lieu of previous ones shown to be untenable, has been followed by a new criticism leading to a new scepticism. All possible conceptions have been one by one tried and found wanting; and so the entire field of speculation has been gradually exhausted without positive result: the only result reached being the negative one above stated, that the reality existing behind all appearances is, and must ever be, unknown.