Justifying an evidence principle

Part of a series which began with Fake news and the ethics of belief.

Time we returned to our proposed evidence principle:

[EP3] If anything is morally wrong, then it is morally wrong to believe anything, within the category of descriptive belief, on insufficient evidence, in the absence of any conflicting and overriding moral imperative.

A principle like this lays on the believer a prima facie burden of justification for acquiring and/or holding descriptive beliefs. To justify a belief morally, the believer would need to demonstrate that either:

(i) It is supported by evidence; or

(ii) By not believing the believer would breach a conflicting and overriding moral imperative.

William Kingdon Clifford
William Clifford, 1901

If there is insufficient evidence, the content of the descriptive belief cannot be used to justify it. We will see later that this will have particular relevance for religious beliefs.

An evidence principle like EP3 which is expressed in moral terms will share general features of other moral principles. For example it will need to ‘fight its corner’ against other principles in those circumstances where an instance of over-belief could potentially be exonerated by a conflicting and overriding moral imperative.

Principles against cheating, lying, stealing – even killing – will similarly have to ‘fight their corner’ at times.

But, again as with other moral principles, it might be over-optimistic to expect a completely comprehensive justification for a principle like EP3. Earlier (see: Less of the sermon) we suggested an underlying rationale for William Clifford’s evidence principle (‘CP’) based on a set of descriptive claims (D1-D13) about human behaviour, plus a generic moral claim which we worded as:

(P1) Other things being equal we should each do what we can to maximise the survival and well-being of others at individual level and the survival, well-being and cohesion of others at community level.

Later we noted that a modified principle like EP3 could share this rationale. But we only claimed the rationale appeared plausible, not that we had incontrovertible proof. So our argument is that someone who believes the set of descriptive claims D1–13 to be substantially true and also holds a generic moral belief like P1 should for consistency adopt a principle like EP3.

This is another feature that EP3 shares with other moral principles. With many if not all moral principles it is possible to frame and defend an opposing position – particularly if the principle and its converse come from opposing world-views.

An example might be Thrasymachus saying in Plato’s Republic that ‘justice or right is simply what is in the interest of the stronger party’,1 contradicting the idea of justice as fairness. Or Pierre-Joseph Proudhon’s 1840 slogan ‘Property is theft’.

So perhaps the most we can hope for is that EP3 makes sense as a moral principle, that it behaves like one and does not entail any contradictory or intuitively unacceptable consequences.

We might also need to position it in relation to the kind of overall world-view it is either compatible with or incompatible with.


1 Plato (1955, 1974) The Republic, 2nd ed, Harmondsworth, UK: Penguin, §338c p77.

© Chris Lawrence 2021

2 thoughts on “Justifying an evidence principle

  1. Pingback: Full awareness | some strong language

  2. Pingback: *Press This* Justifying an evidence principle #174 | Its good to be crazy Sometimes

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