It is wrong to believe on insufficient evidence

The ethics of belief

William K. Clifford 1845 · 1879It is wrong always, everywhere, to believe anything upon insufficient evidence.

What it claims

It is wrong, always, everywhere, and for anyone, to believe anything upon insufficient evidence, even if the belief turns out to be true.

Why

No belief is truly private: a poorly grounded one makes us gullible and can harm others, which honest inquiry would have avoided.

The same idea through history

David Hume1748Hume writes that a wise man proportions his belief to the evidence. Clifford turns this rule of prudence into a moral duty.

William K. Clifford1877In "The Ethics of Belief" (Contemporary Review, January 1877), he argues that the question "do I have the right to believe?" is a moral question, not just an intellectual one.

Thomas Henry Huxley1889Huxley states a similar rule: it is wrong to claim certainty without evidence. William James quotes the two side by side in "The Will to Believe".

In short

"It is wrong to believe on insufficient evidence" is an argument by William K. Clifford ("The Ethics of Belief", 1877, 1877) on the question "Should we believe without proof?" (answer: no belief without evidence). Its claim: It is wrong, always, everywhere, and for anyone, to believe anything upon insufficient evidence, even if the belief turns out to be true. According to AskPhilosophy's logic check (Z3 solver), the argument is valid only if one grants a premise the author leaves unstated (P5). AskPhilosophy presents 4 objections, 2 of them with a documented reply, and the original text behind each premise, checked word for word.

"The Ethics of Belief", 1877

Valid with an implicit premise

A shipowner has to send an old emigrant ship to sea. He has doubts, and they torment him. So he persuades himself that Providence will protect these families, that the builders are honest, that the ship has already come through safely. He believes it sincerely, and the ship goes down. Clifford asks: what should we say of this man? He is guilty, he answers, for he had no right to believe on such evidence. And if the ship had arrived safely? He would be just as guilty: he would merely have been lucky. For Clifford, a belief is not a private matter. Each of us, in believing, builds a little of the world in which others will live. Hence the famous rule: it is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.

Checked by a logic solver: the premises cannot all be true while the conclusion is false.
Without the implicit premise: Without P5, the computer finds a case where a belief on insufficient evidence harms others, where an honest inquiry could have avoided it, and where it is nevertheless not a moral fault: a mere misfortune, like a spreading disease, with no one responsible.

With P5 the argument is valid: a belief on insufficient evidence does harm (P2 to P4), doing harm when one could have avoided it is wrong (P5), and this wrong does not depend on the outcome (P1). Without P5 it is no longer valid: nothing then says the harm described is a moral fault and not only a risk. The critics aim precisely at P5 and P4: the principle can be seen as too severe, or as one that contradicts itself (see the objections).

Analogy. A doctor prescribes a drug without having read the test results, telling himself it will be fine. The patient recovers. Did the doctor act well? No: he was lucky. For Clifford, believing on insufficient evidence is doing the same with one's ideas: a happy outcome does not erase the fault.

Objections

Each objection is a conversation: click to see who replies and where the debate stands.

William James 1896 · attacks the conclusion

The duty to "avoid error" and the duty to "find the truth" are two separate laws. Clifford puts the first far above the second. But this choice is itself only a passion, the fear of being duped. James finds the exhortation fantastic: it is like a general telling his soldiers that it is better never to go into battle than to risk a single wound.

no reply

No reply possible: objection raised in 1896, after the author's death (1879).

The debate goes on (our summary) Clifford died in 1879, seventeen years before James: he could not reply. Two replies can be imagined on his side. First, he distinguishes believing from acting: he admits that one must sometimes act on probabilities (II, §2). Second, for him the duty to avoid error comes not from fear but from the harm done to others (P2 to P4). James replies to this elsewhere: a world where one always suspends judgment is not without risk either. See James's argument, "The Will to Believe".

Objection anticipated by Clifford attacks the conclusion

Are we then to become universal sceptics, afraid to put one foot before the other until we have personally tested the firmness of the road? Nobody can check for himself a hundredth part of what he believes. And shall we steal and lie because we have no personal experience that proves it is wrong?

Clifford replies

Clifford 1877 · Clifford's reply (testimony)

One may believe a chemist on his word, if one knows nothing against his character or judgment. His training encourages honesty, and a non-chemist can understand enough of his methods to see that someone could in principle verify his result. His authority is valid because others test it.

Clifford 1877 · The limit of authority

But the same chemist deserves no trust when he says that an atom of oxygen has stayed unaltered throughout all time: no one can know that without ceasing to be man. No eminence of character or genius gives authority to state exact and universal knowledge.

See the rest of the debate (1)

Clifford 1877 · Clifford's reply (acting without believing)

This fear is groundless: the principles most fitted to guide life stand out more clearly the more carefully they are examined. And there are many cases where it is our duty to act on probabilities, even though the evidence does not yet justify belief, because it is by acting that evidence is obtained.

Objection anticipated by Clifford attacks premise 5

"I am a busy man; I have no time for the long course of study which would be necessary to make me a competent judge of certain questions, or even to understand the nature of the arguments."

Clifford replies

Clifford

In that case, Clifford answers, he should have no time to believe either.

The debate goes on (our summary) The answer is short and hard. It leaves a question: must someone who has no time to form an opinion on a subject really believe nothing, not even what everyone around him believes? Clifford answers this in the second part of his essay, through testimony and authority (see the previous objection).

Alvin Plantinga 1983 · attacks the conclusion

Clifford's rule does not stand on its own feet. Plantinga argues that classical evidentialism (having the right to believe only what is proved from certain beliefs) is incoherent: its own rule is neither self-evident nor provable from such beliefs. If the rule were applied to itself, one would have to stop believing it.

no reply

No reply possible: objection raised in 1983, after the author's death (1879).

The debate goes on (our summary) Clifford could not reply. A defender can say that his rule does not claim to be proved by evidence but is grounded in its effects on others (P2 to P4). One can answer in turn that this reason is itself a thesis that would have to be established by evidence. The debate on this point is still open.

What today's voices say

Defend it

Peter SingerUses Clifford's shipowner story: you cannot just have faith, you need to check the evidence, because lives are at risk.

Wesley HuffHe accepts that belief should follow evidence and says he would drop his faith if the Gospels were unreliable, but he also holds that conviction is the Spirit's work.