Guest Blogger, Dr. Kevin Kinghorn, Associate Professor of Philosophy and Religion at Asbury Theological Center, D.Phil., University of Oxford, The Queen’s College

Sometimes the objection is made that religious hypotheses, unlike scientific hypotheses, aren’t open to verification through observation.  The objection goes something like this: “There’s no way ever to show conclusively that Christianity is true or that it’s false.  If we’re going to make progress in understanding the world, it would be helpful to stick with theories that can be tested by observation and either conclusively verified or conclusively shown to be false.  Otherwise, why should anyone take a non-verifiable theory seriously?  If someone wants to claim that God exists, that angels exist, or that any other kind of supernatural stuff exists, then fine.  But if the claim could never be verified through observation and induction, why should anyone take it seriously?”

I think this is a common view of how many people see the difference between scientific theories and religious theories.  Scientific theories are subject to evidence and observation, and they’re open to critical engagement by thoughtful people; and religious theories involve extravagant claims that could never be conclusively tested. 

This objection strikes me as unfair because it fails to acknowledge that theists and scientists are often in the same boat.  The objection supposes that a scientific theory only gains credence as it is empirically verified.  But this is emphatically not the case.  If it were the case, we’d have had a whole lot less scientific progress over the past centuries!

Many times in science, a theory will gain credence not because it has somehow been observed.  Rather, it gains credence because it explains what we do observe.  For instance, in the 19th century the existence of the planet Neptune was affirmed by astronomers before it was observed and seen clearly by telescope as in fact a planet.  Astronomers were charting the orbit of Uranus, which they were observing by telescope, and they noted that Uranus’s orbital path was not as was expected.  What best explained this observable data of Uranus’s orbit?  The best theory seemed to be that the gravitational pull of some further, as-yet-unobserved planet was pulling Uranus off its expected course.  The theory itself of a further planet (i.e., Neptune) wasn’t observed.  But if scientists concluded that the existence of this further planet was the best explanation—i.e., was the theory that best explained the data that was observed—were those scientists somehow being ‘unscientific’?  Surely not.  Scientists have often explained observed data in terms of unobserved phenomena.  That is, they have often concluded that some hypothesis, while itself not observed, nevertheless serves as the most likely explanatory theory of some set of data we do observe. 

Theists are in just this position.  They start with the observed data of this physical universe.  And they conclude that God (an unobserved hypothesis, if you will) is the best explanation for this observed data. 

Perhaps the objector will insist that I am ignoring a crucial difference between the hypothesis of Neptune and the hypothesis of God: Neptune can at least in principle be observed (and later was of course observed by telescope), whereas God cannot be observed.  Three responses might be offered.  First, if we acknowledge this point, it nonetheless doesn’t impact the points made in the previous paragraphs.  Second, we might insist that, actually, God can in principle be observed; it’s just that we may need to get to heaven before we meet the resurrected Christ.

A third response would be to point out that, as a matter of fact, accepted scientific theories needn’t even in principle be observable.  I’ll set aside widely accepted theories about quarks and other elements within the field of quantum physics; and I’ll set aside widely accepted theories about dark matter and other elements with grand theories in cosmology.  (It’s interesting to note, though, that scientists tend to defend their beliefs about such things largely by explaining why they’re the kinds of things that we really can’t observe.)  Instead let’s consider something we can probably all agree on: the existence of black holes. 

A black hole is of course a point or region of infinite density, from which nothing—not planets, stars, or even light itself—can escape.  It’s a hypothesis that explains a lot of what astronomers observe throughout the universe.  Can a black hole be observed, even in principle?  Well, if not even light is escaping from it, a telescope isn’t going to be much good.  What other ways might we observe a point of infinite density?  If we’re at a loss to suggest an answer, we by no means need to give up our beliefs about black holes.  They explain a whole lot of what we do observe when we point telescopes into outer space.  And so, even though we don’t actually observe a black hole, astronomers still affirm the hypothesis of a black hole as the simplest, best explanation for the pattern of stars and planets they do observe within some galaxy.    

The point to all this is again that scientists are often in the same boat as theists.  They observe the facts of this world, and they may find that the best explanation for these facts lies in an unobserved hypothesis.  Though they observe only the effects of this hypothesis, as opposed to observing the hypothesis itself, this point itself in no way means that the hypothesis in question is somehow not an appropriate one or one that is most likely not true.