Science seeks to explain the world. While philosophers have developed elaborate criteria for what constitutes an explanation without coming to a consensus, it has always seemed to me that a good scientific explanation has two primary characteristics:
- Complicated things are explained in terms of simpler things that are easier to understand or, more commonly, are already understood.
- Psychological puzzlement is reduced when an explanation is provided. There may still be puzzlement, but it should be either reduced, or relocated to some other unrelated phenomena.
These general considerations may explain why so few scientists are attracted to the explanations provided by the intelligent design movement. When an intelligent cause is offered as the “explanation” for certain phenomena, the explanation is more complicated than the phenomena. For example, if certain information-rich strings of DNA were assembled by an intelligence intervening from “outside,” that intelligent agent would be way more complicated than the string of DNA. We have greatly complicated our “system” by adding this designer to the mix of things that have to be organized into an explanation. We are trying to explain something relatively simple in terms of something very complicated.
The oft-used example of Mount Rushmore being the product of an intelligent agency is misleading. We can certainly detect that it is designed and we know that we must invoke intelligent—in this case human—designers to account for it. But our understanding of human behavior has been developed and refined over millennia. We take for granted that the patterns that make up the faces on Mount Rushmore pre-exist in the minds of the artists who did the work. Our “explanation” is really nothing more than a statement that a pattern has been transferred from the minds of the designers to the side of the mountain.
It seems to me that this winsome example conflates cause with explanation. Very little is truly “explained” by saying that a pattern has moved from one place to another.
A different example makes this point clearer. Suppose you find your friend with a bullet hole in his head and you wonder if this was a stray bullet or an assassination. You find a video recording and discover that there clearly was an assassin. So the death was “intelligently designed.” But is the assassin on the video the “explanation” for the death or simply the “cause”? Unlike the Mount Rushmore example, we lack a ready-made explanation for why an assassin would kill your friend. The identification of intelligent cause does not explain the phenomena at all.
The problem of puzzlement is similar. If we say that an intelligent agent has produced certain strings of DNA, are we more or less puzzled by the problem of DNA when we are all done? Frankly, I am more puzzled after hearing this claim. This “explanation” generates a set of questions even more troubling than our original query about how information-rich strings of DNA came to be. For example, what about DNA strings that look like gibberish? Why did our intelligent agent produce an information-rich string and sandwich it between two pieces of nonsense? Why do so many pieces of DNA look “broken” like our gene for making Vitamin C? And, how exactly, did our agent produce the strings in question? Dozens of additional questions arise.
Puzzlement is increased, not decreased by invoking an intelligent agent to explain natural phenomena. Scientists will thus not feel like they are making progress with this line of investigation.
Neither of these two key points can be formulated into a rigorous demarcation argument that neatly divides good scientific explanations from bad ones. French physicists, following Descartes, opposed Newton’s theory of gravity for decades. They thought the claim that bodies could reach across empty space and pull on each other so ridiculous—so puzzling—that they championed an alternative theory. In 1700 it would have been hard to resolve this question to everyone’s satisfaction. But the Newtonian effort had a vitality that carried it steadily forward until eventually the French alternative passed into the dustbin of history.
Complexity and simplicity are not as simple as they appear, however, so applying such criteria is far from trivial. Complexity does not, for example, have anything to do with how hard an explanation is to understand. Einstein’s Theory of Relativity is harder to understand than the ideas of Newton that it replaced, but this is not because it is more elaborate or more complex. The challenges of understanding relativity come entirely from the associated mathematical equations that are harder to solve. There is a useful comparison with language here.
Imagine that all recipes for making cookies were written in Chinese and all recipes for making cakes were written in English. English speakers would find cookie recipes hard to understand; Chinese speakers would find cake recipes harder to understand, although their enthusiasm for bilingualism would certainly be helpful. The complexity of an explanation has to do with its “moving parts.” How many different components? How many time intervals have to be measured? How many subtle interactions have to be tracked? Is the history of the system relevant? How many interlocking phenomena have to be noted and related to each other? Regardless of the languages in which they were written, we would all agree that recipes for cake are more complex than recipes for chocolate milk.
The question of puzzlement is also complicated. What does it mean to say that “puzzlement is reduced” and how large a reduction is required for that process to be considered meaningful? One of the most puzzling features of the natural world, that perplexed astronomers for 2000 years, was the observation that the planets occasionally moved “backward” in the sky, executing what looked like loop-de-loops. Various complicated explanations were provided, the last one being that of Copernicus in his landmark book in 1543. Copernicus solved the problem by suggesting that the earth moved around the sun and the apparent backward motion of the planets was just an optical illusion created when the earth passed other planets in its orbit about the sun.
Copernicus’s breakthrough was not immediately hailed as a great explanation, however, because so many questions were raised by his claim that the earth moves. Many people were quite troubled by the claim that the earth was hurtling through space at unimaginable speeds without so much as a breeze or wobble. This seemed far more puzzling than the loop-de-loop motions of the planets. It was not until Galileo worked out the physics of a moving earth, and Newton showed how gravity could keep the earth in a stable orbit, that the new Copernican system seemed less puzzling.
Concepts like complexity and puzzlement are imprecise—clear in a general sense, but foggy around the edges. There is room for disagreement. And this is why it is so important to appreciate that science is a communal enterprise. A group of experts needs to brainstorm, argue, and even quarrel about explanations to make sure they are adequate. One of the greatest strengths of science is the way that skeptical critique has been built into the process. Many scientific ideas are stillborn because skeptics make demands that cannot be met and the futility of those ideas is quickly exposed.
Scientific progress has a certain “feel” to it and anyone who has spent time in a research group knows that feeling. There is a shared intuition that explanations are “drilling down” to ever more fundamental levels of reality. DNA is explained in terms of molecules; molecules are explained in terms of atoms; atoms are explained in terms of electrons, protons, and neutrons. Protons and neutrons are explained in terms of quarks. Puzzlement drives the enterprise but it seems to gradually and steadily reduce over time. Astronomers no longer fret over the many things that puzzled Copernicus.
Intelligent design does not “feel” scientific. It may not be the “science stopper” that some of its critics claim, but it seems to lack explanatory momentum. After nearly two decades of energetic exploration it seems to me that it should be going somewhere. We should be able to see how the initial ideas led to explanations that identified new questions and how those questions provoked investigations that uncovered ever more adequate explanations. The world should seem less puzzling now than it did.
But none of these things have happened, which explains why the initial goals of the Intelligent Design Movement have not been met, why the scientific community is paying no attention, and why Christians looking to understand the Creation should be skeptical.