Could Miracles Happen?

Another great article on Aeon magazine this week is about why no one should believe in miracles, by Lawrence Shapiro.  Shapiro takes a tasty stock of Hume’s argument against miracles, adds a dash of Bayesian epistemology, and rounds things off with a nice discussion of the base-rate fallacy—surely worth a read.  But after reading it, I wondered why we don’t use this much simpler argument against supernatural intervention:

THE A PRIORI ARGUMENT:

1. Miracles violate the laws of nature.
2. The laws of nature are exceptionless—that is, they are (expressed by) true universal generalizations
3. Conclusion: There are no miracles.

The argument is valid, and both of its premises have a claim not merely to truth, but to conceptual truth. The first premise is a characterization of what makes God’s miraculous action supernatural: miracles contravene or override the natural laws which govern the world.  The second premise is guaranteed by most views about the laws of nature, but anyway here’s a quick argument for it: the laws of nature are nomically necessary, and necessity implies truth.  So the laws are true.  Unless something has gone wrong, we don’t merely have inductive reasons to doubt that miracles have happened (as Hume and Shapiro claim) but a priori reason: the very idea is conceptually incoherent. But of course this argument is too quick: though we may have good reason to doubt that miracles have happened, that reason is not conceptual incoherence.  What went wrong?

We could deny premise 1: perhaps there’s a way of characterizing supernatural intervention that doesn’t rely on it’s being above the petty rules which govern mortal mechanics.   We’ll return to this idea in a bit.  First, though, I’d like to look into relaxing the second premise.  Could a law of nature be false?

Some people think so—Nancy Cartwright chief amongst them.  But she’s an outlier, and most theories of natural law back premise two.  Foremost amongst these is dispositional essentialism: According to this view, advocated by Brian Ellis and Alexander Bird, the laws express the essential natures of the properties they involve.  So if Coulomb’s law is a law of nature, it’s an essential property of charge that charged objects obey Coulomb’s law.  Since things have their essential properties at every world in which they exist, charged objects must—and do—conform strictly to Coulomb’s law.

Humeans, on the other hand, take laws to be mere regularities, not backed by essences or necessity.  Now these regularity theorists have some explaining to do: why are some generalizations laws, and others mere accidents?  What is the difference between “Like charged particles repel one another” and “all of my coffee mugs are dirty”?

The regularity theorist’s answer is pragmatic: laws are tools used to organize our knowledge into a deductive system. “like charged particles repel one another” is inferentially very useful; “all of my coffee mugs are dirty” is not.  This insight leads us to the Best Systems Account of laws (BSA), associated with John Stuart Mill, Frank Ramsey, and David Lewis:  the laws of nature are those true generalizations which, taken together, form the simplest, strongest axiomatic system of all of the truths of the world—where a system is simpler if it has fewer axioms, and stronger if it implies more truths.

We can imagine assigning a score to each potential lawbook: points are gained by having true consequences, deducted for having more axioms.  The group of true generalizations which scores highest is the lawbook of our world.

This characterization of laws gives regularity theorists more room to maneuver than dispositional essentialists.  The dispositional essentialist held that laws are true because they are metaphysically necessary; the Humean holds that laws are true because true generalizations better organize knowledge than false ones.

So it’s not against the spirit of Humeanism to relax the truth condition if adding some false generalization to our deductive system would yield a simpler system from which very many truths and very few falsehoods could be inferred.  We’d just need to tweak our scoring rules a bit: a potential system of laws gets points added for each true consequence, points deducted for each axiom, and points deducted for each false consequence.  Presumably, these will be weighted—one false consequence should remove many more points than each true consequence.  Call this the Good Enough System Account of laws (GESA).  The laws of the Good Enough System can have exceptions, provided the exceptions are few, and the laws are otherwise quite useful.

Now, if the GESA of laws is right, we shouldn’t be so sure of Premise 2 of the a priori argument.  We might have good reason to think that miracles don’t happen, but they aren’t ruled out by fiat.

Of course, we might also want to deny premise 1.  Remember, Premise 1 sought to express what was miraculous about miracles: God’s direct interventions violate the laws that govern mortal mechanics.  But God’s interventions must be interventions, that is, they must really cause things.  And causation requires subsumption under laws.  So while in order for divine intervention to be divine, it must break the natural laws, in order for it to be intervention, it must obey some law.  What gives?

Here, I think, we should distinguish between fundamental and nonfundamental lawhood.  Even in mortal contexts, we are willing to countenance not-strictly-speaking-true nonfundamental laws (read: the special sciences) but not false fundamental laws (read: physics).  This makes the GESA more closely aligned with how we think of special sciences, and the BSA—with its stipulation that the laws must be true—closer to how we think of fundamental science.  (The view we’ve arrived at is similar to Craig Callender and Jonathan Cohen’s Better Best System account, but allows us to distinguish the fundamental laws from the nonfundamental: the fundamental laws are true, whereas the nonfundamental laws may not be).

The believer in miracles, then, takes the fundamental law to be divine: “what God intends comes to pass”.  But this doesn’t leave her bereft of mortal mechanics: instead of being strictly true, the natural laws of physics are nonfundamental laws: most of their consequences are true, but their usefulness to us isn’t impugned by those miraculous occasions when they lead us astray.

Don’t get me wrong, though—while I think the a priori argument is unsound, denying it shouldn’t make us more willing to countenance miraculous intervention.  Hume’s argument, and Shapiro’s, should remind us that believing miracles actually happen is, nearly always, irrational.