To that end, I draw upon neglected 18th-century source materials from the Anglican Bishop William Fleetwood, the philosophers Mary Astell and George Turnbull, a dissenting minister named Caleb Fleming, and William Adams, the eventual Master of Pembroke College. I channel their collective insights to show that any method which assigns a severe improbability to miracle claims based on their exotic causal features makes two interrelated conceptual mistakes. First, any such method misapplies the concept of evidence. Second, the previous mistake is due to an even deeper misapplication of the concept of a communication vehicle. Let’s consider a brief sketch of these two points in tandem.
First, I show that defenders of Hume misapply the concept of evidence because they violate an adequacy condition on the evidence relation—viz., that hypotheses cannot be disconfirmed by their own successful predictions. Miracles are extremely rare by definition and so that predicts the observation that they are extremely rare. Thus, the observation that they are extremely rare cannot disconfirm miracle hypotheses. One might suspect, however, that this result stems from formal trickery unless we get an independent explanation for why miracles must be rare. This brings us to the second point.
Miracles must be rare because they have the same metaphysics as linguistic artefacts. Miracles aren’t simply synonymous with divine intervention more broadly. They are, more specifically, a form of speech. Since miracles are essentially vehicles of communication, they require displays of juxtaposed heterogeneous properties to realize epistemic values that typographers would call legibility and readability—i.e., the ability to recognize and decipher symbols as well as understand their meaning. Consider the example of a standard document with black lettering foregrounded against a white background. This juxtaposition generates disproportionate patterns between two types of things. But it is epistemically inappropriate to convert the disparity of white-to-black spatial units into probability assignments about the existence of a document. It is likewise with miracles, where nature’s common course is like the white background and the exotic event is like the black lettering. Nature’s predominately ordinary course is necessary for miracles to transmit their messages in the way that an environmental backdrop is necessary to enable the transmission, intelligibility, and strength of a signal. Thus, an increase in rarity corresponds to an increase in contrast with daily experience to bring about an increase in signal clarity. Humean approaches fail in the case of miracles only because they would fail when applied to cases of communication more generally.