It is not too difficult to see the flaws in “God of the gaps” reasoning: “gaps” in Science have a funny habit of being filled. In fact, some people think that scientific “gaps” are filling so well that Science will soon be able to answer all questions – eliminating God in the process. According to them, theism (a redundant hypothesis with no explanatory power) will be summarily rejected as Science continually expands Its frontiers. In essence, these people are advancing a “Science of the gaps” argument; rather than assuming that God will fill the gaps, they are assuming that Science will. (It should be noted that most of these people are not scientists; scientists, by and large, recognize the confines of their discipline.)
Regrettably, “Science of the gaps” arguments have received much less critical scrutiny than “God of the gaps” arguments have. I say this is regrettable because “Science of the gaps” arguments are just as suspect as “God of the gaps” arguments are (if not more so).
This is probably not how it happened.
I should probably begin by explaining what I mean by “Science.” (This is by no means the place for a rigorous definition of Science, but some rough account will suffice.) The word “Science,” in my mind, refers to the aggregation of current human theories and knowledge regarding the empirical (i.e., observable) world.
In light of this preliminary definition – which briefly encapsulates the who (people), what (current theories and knowledge), and how (observation) of Science – I would like to reflect on some (not all) of Science’s necessary limitations and their impact upon “Science of the gaps” arguments.
First of all, Science is fundamentally human. It consists of human ideas extrapolated from human observations, and is therefore circumscribed by the boundaries of human experience and human thought (like any human endeavor).
Unfortunately for Science, human experience is significantly constrained. I could focus on the fact that we only have five main observational tools (the five senses) or on the fact that our observations are fallible at best and completely unreliable at worst. Instead, however, I will point out that we humans are only physically capable of observing a very tiny fraction of spacetime. What was the universe like one million years ago? The simple answer is that we do not know for sure.
Fortunately for Science, a small amount of observational data can be universalized into general theories. An apple that falls from a tree can become the law of gravity. What was the universe like one million years ago? We may not know for sure…but we can certainly infer.
There’s a catch, though: a lot of different theories can explain the same data. Newton’s law of gravity certainly explained the apple that fell on his head – but if Newton had instead postulated that an invisible poltergeist was harassing him with projectile fruit, no one would have been able to tell him that his idea “did not account for the data.” (After all, “gravity” is just as invisible as poltergeists.) And yet, our intuition is that the law of gravity is (for the most part) very reasonable, while speculation about poltergeists is stupid. In other words, we have an intuition that there are non-empirical criteria by which our theories about the empirical world should be evaluated. One such criterion is Occam’s razor: entia non sunt multiplicanda praeter necessitatem (entities should not be multiplied beyond necessity). Another is inductive reasoning; if apples always fall down to the ground rather than floating up to the sky, then it is reasonable to expect future apples to fall and not to float.
This means that the entire scientific enterprise depends not only on empirical data, but also on basic intuitions about how the world works – philosophies of science. Science can only exist when certain philosophical assumptions about metaphysics (how things fundamentally are) and epistemology (how we know things) are made.
That, in and of itself, is enough to refute “Science of the gaps” arguments. Whether or not God exists is a metaphysical question – a specific kind of philosophical question –not a scientific one. Science alone cannot answer that sort of question.
Perhaps it is clear enough that Science alone cannot answer theological questions. But there are plenty of other sorts of questions that Science alone cannot answer: “Why is there something rather than nothing?” or “Why does the universe behave according to predictable principles and ‘laws’?” Science might be able to tell you how the “something” works or describe the predictable principles according to which the universe behaves – but nothing (or not much) more.
Since there is no clear line demarcating “Science” from “not-Science,” arguing that Science can or cannot answer all questions is, in a way, futile. But it should be obvious (I hope) that Science is not going to kill God, just as God cannot kill science. On the contrary, God must be evaluated on philosophical and theological grounds.