Thus far this week, I have restated Hume’s “hearsay argument” against transubstantiation (see here) and surveyed some possible exceptions to the hearsay rule in law that might be application to the case of transubstantiation (here). But what is my position regarding this controversy? Am I with Hume or Augustine?

To the point, I would apply the “Principle of Indifference” — an idea from the domain of probability theory — to the question of transubstantiation and the theology of Jesus’ Last Supper. This principle, which can be traced back to John Maynard Keynes’s Treatise on Probability (1921, pp. 41-64), applies when two conditions are met: (i) you are considering two or more mutually-exclusive hypotheses, such as the possibility of transubstantiation during the celebration of the Eucharist, but only one of which can be true, and (ii) you have no direct evidence to favor one possibility over the others. In that case, when you have no direct evidence to favor one outcome over another, you should assign equal probability to each hypothesis.

Or in the words of Lord Keynes (ibid., p. 42) himself:

“The Principle of Indifference asserts that if there is no known reason for predicating of our subject one rather than another of several alternatives, then relatively to such knowledge the assertions of each of these alternatives have an equal probability. Thus equal probabilities must be assigned to each of several arguments, if there is an absence of positive ground for assigning unequal ones.”

In closing, although transubstantiation has all the hallmarks of a self-sealing conspiracy theory (e.g., emotional appeal, unfalsifiability, and in-group/out-group dynamics between true believers and heretics), at the same time both of the conditions mentioned above apply to the case at hand, since we have no direct evidence one way or another telling us whether transubstantiation is true or not. Contra Hume, then, I would start any discussion of the Last Supper by assigning a 0.5 probability to the possibility that transubstantiation might be true. Keep this conclusion in mind as we consider Hume’s other arguments against the possibility of miracles … (to be continued)