While preparing for the philosophy of religion course I’m teach this summer, I just came across Peter van Inwagen’s essay “Quam Dilecta”. The essay appears in God and the Philosophers (1994, Thomas Morris, ed.), a collection of autobiographical essays where the authors (professional philosophers of varying distinction) explain
how they personally see the relationship between the spiritual and the philosophical in their own lives, or else [show] with their own stories how a person of faith can grapple with some of the problems and prospects of religious belief from a philosophical point of view. (p. 4)
At the end of his essay, van Inwagen presents his reasons for trusting “the Church” rather than “the Enlightenment”. There is much (much) one could say about these reasons, but, there is no need to, since van Inwagen himself admits that he believes what he does on the basis of “insufficient evidence”. However, prior to giving his (insufficient) reasons for “trusting the Church”, van Inwagen dedicates a section of his essay to explaining why he rejects the demand for sufficient evidence. This is the section of his essay I’d like to say just a little about here.
The principle that states that it is always wrong to believe on the basis of insufficient evidence has come to be known as “Clifford’s Principle”. W. K. Clifford gave the first clear statement and thorough (but partially unsuccessful) defense of the principle in his Ethics of Belief (1879). Van Inwagen (implicitly) acknowledges that most people agree that Clifford’s principle must be qualified with some such statement as “when the consequences of one’s belief or lack thereof are potentially significant”. But van Inwagen has a deeper complaint. He complains that
Clifford’s Principle is almost never mentioned except in hostile examinations of religious belief, and that the antireligious writers who mention it never apply it to anything but religious beliefs. (pp. 44-45)
Van Inwagen notes in particular that Clifford’s Ethics of Belief appears in almost every philosophy of religion anthology but no epistemology anthology.
But why don’t philosophers apply Clifford’s Principle elsewhere? According to van Inwagen
If Clifford’s Principle were generally applied in philosophy (or in politics or historiography or even in many parts of the natural sciences), it would have to be applied practically everywhere… we’d all be constantly shoving it in one another’s faces… If we generally applied Clifford’s Principle, we’d all have to become agnostics as regards most philosophical and political questions, or we’d have to find some reasonable answer to the challenge: ‘In what sense can the evidence you have adduced support of justify your belief when there are many authorities as competent as you who regard it as unconvincing?’ But no answer to this challenge is evident. (p. 45)
So van Inwagen thinks that A) the fact that apparently equally intelligent and informed people disagree on most philosophical and political questions implies that the evidence that either has adduced in favor of her position is insufficient and B) we have all (at least tacitly) acknowledge (A), and therefore resist applying Clifford’s Principle because we know it would lead to widespread agnosticism.
Even without considering alternative explanations, van Inwagen’s should seem a little implausible: we all (tactily) recognize that applying Clifford’s Principle would lead to widespread agnosticism on philosophical and political views?! How many of us even believe (A) is true?!
But, since I’m a big fan of IBE, I think the best way to undermine van Inwagen’s explanation is to present an alternative one. How about this: religion is the one area where many if not most people readily admit that they hold their beliefs on the basis of insufficient evidence. Reminding someone of Clifford’s Principle isn’t going to do one bit of good if that person believes that he is holding his belief on the basis of sufficient evidence. Why is Clifford’s The Ethics of Belief included in philosophy of religion anthologies but not epistemology anthologies? For the same reason that intro to philosophy courses (students of which are the primary consumers of philosophy of religion anthologies) include sections on “faith vs reason”: many if not most student readily admit that they hold their religious beliefs on the basis of insufficient evidence. Hence, the question of whether they should do so is a very relevant one! Again, if someone believes that she is holding her belief on the basis of sufficient evidence (as is the case most of the time in all other areas of philosophy and politics), there is simply little point in discussing with her the question of whether she should hold her belief on the basis of insufficient evidence. Rather, you should discuss with her whether the evidence is indeed sufficient (and this is exactly what happens, even if not very effectively, most of the time in all other areas of philosophy and politics).