Here’s a proposal for how to think about evolution if you want to believe in divine providence: Even if science explains the “efficient causes” of evolution, God can be the “final cause.”
Aristotle argued that “Why?” can generally be answered in four ways simultaneously. The efficient cause is a preceding event that reliably generates the result, as my finger hitting the keyboard causes a letter to appear on the screen. The material cause is a characteristic of the object involved. For instance, my computer is so structured that it produces letters when touched in a certain way. (Perhaps a better example: I am communicating right now because it is in the nature of the substance known as “mind” to think and to express its thoughts.) The formal cause relates to the essence or definition of the object. For instance, my computer generates letters because that’s what computers do; that’s its “form”. And the final cause concerns goals and purposes. I type these letters in order to communicate certain ideas to you.
Modern science began when Francis Bacon argued that experiments could (only) reveal efficient causes. Since Bacon, scientists have considered Aristotle’s material and formal causes to be simplifications of efficient causes. If you want to know how a computer works, you really need to understand a chain of predictable events. To say that a computer is an object that generates text (an example of a formal cause) is not to explain it.
As for final causes, they are not detectable by science. According to Bacon, natural events don’t happen for a purpose; they happen because something else happened first and led regularly to the result. Without Darwin, we would assume that there were final causes in the biological world, for organisms seem to move and evolve toward goals. But biology since Darwin has been free of final causes (it has become “non-teleological”). For example, biologists do not really believe that genes are “selfish” and “want” to propagate. Rather, genes mutate as a result of prior chemical processes, and the mutations that help organisms survive tend to proliferate. It is unnecessary to cite purpose. Higher organisms have wills and goals, but those arise because of prior, physical causes.
Stripping the natural world of purpose upsets religious believers. In fact, I can understand that a non-teleological universe is profoundly disturbing; nothing has a purpose. Thus some believers are moved either to deny that evolution has occurred at all, or to claim that an “intelligent designer” is the efficient cause of evolutionary change.
The latter is a dangerous strategy–on theological grounds. Efficient causes should be detectable by experiments. To hypothesize an efficient cause is to make an empirically testable claim. In theory, an experiment might reveal the existence of a hidden intelligence–or it might not. Or (in principle) it might detect an intelligence that is fairly powerful and fairly wise–but that would not be the Judeo-Christian/Islamic god, who is all-powerful. Real omnipotence cannot be detected, because all that one can ever see is a finite quantum of power. I am reminded of the controlled experiments that (supposedly) find a statistically significant effect from prayer. To claim that invoking God has an effect of a few percentage points strikes me as almost blasphemous. Is this the God of glory who thundereth, who breaketh the cedars of Lebanon?
Besides, any efficient cause is itself an effect. If we were to discover an Intelligent Designer who plays with genes to achieve certain ends through evolution, then we should be able to explain what caused that designer to exist. But God has no efficient cause.
Thus I think orthodox monotheists should choose a different course. They should accept Bacon’s idea that efficient causes are detectable by experiments. But God should not be subjected to such tests; that would not be compatible with faith or with the concept of omnipotence. Still, efficient causes can co-exist with final causes. Perhaps homo sapiens evolved because of a random genetic mutation in a primate ancestor (that would be the efficient cause of our species). At the same time, people could have evolved in order that God would have the opportunity to sacrifice His only-begotten son. The latter claim would be untestable, but it would follow logically from faith and revelation.
People who accept this recommendation (which has surely been made before), cannot find a justification for teaching “intelligent design” in science classes. However, they can be confident that no experiment will ever threaten their faith or reduce divine power to something observable and (therefore) finite.