This is the final installment in a series inspired by exchanges with Jerry Coyne. Readers might want to read the first in the series for orientation.
The final straw man I want to torch in this series is the claim that science uses evidence and religion uses faith, with evidence being defined as “good reasons to think something is true,” and faith being defined as “the willingness to accept truth claims with nothing to support them.”
Let me start by noting that evidence is not available in the same way to all investigations. There is good evidence available to the geologists that the earth is old, to the chemists that molecules are made of atoms and nothing more, to the astronomer that the universe is expanding, to the economist that endless printing of money will lead to inflation, to the historian that Winston Churchill did indeed exist. But there is little to no evidence available to the cosmologists that there are many universes, to the psychologists that free will is real, to the economists that “trickle –down” stimulus works, to the historian that John Adams liked to sing in Latin while he was taking a bath.
The idea of an evidentiary spectrum is helpful here. At one end we have hard sciences like physics and chemistry where evidence is readily available and we should have very high expectations that truth claims will have a firm foundation. Things get a little murkier when we get to biology and a lot murkier when we consider the social sciences. Consider history as an example. Historians deal with events from the past but the available “facts” are often so incomplete that deep mysteries remain about such basic things as the population of North America when Columbus arrived in 1492.
Faith plays different roles in different disciplines. The physicist needs no faith to accept the law of the conservation of energy. There is no need for the chemist to have faith in the periodic table. The factual evidence is so great that faith is simply not needed. But evolutionary biology needs some faith. The reconstructions of the history of life on this planet require the postulation of species for which there is no direct evidence. Most of the “common ancestors” are hypothetical in the sense that they have to be constructed indirectly with methods that are far from flawless. I think the evolutionary biologists are doing a great job with this—read Coyne’s excellent Why Evolution is True, if you are skeptical—but the enterprise requires inferences that look very much like little leaps of faith.
But what about fields like sociology or economics? I think we can all agree that these are legitimate sciences, but their conclusions require an understanding of how vast populations will behave under conditions that cannot be specified with much precision. Some economists think that tax credits motivate people to buy houses, or trade in their cars. Others think such credits are a waste of money and simply subsidize purchases that were going to occur anyway.
Smart people in the Bush administration thought that temporary tax cuts were a good idea to get the economy growing. Equally smart people today think it was a terrible idea. Every night on CNBC you can hear economist Larry Kudlow extolling the power of supply side economics while economist Robert Reich says just the opposite. Obviously such disagreements cannot be based on simple “facts” for everyone has the same facts. There are some different things going on with economics than with the periodic table of the elements.
So how do we understand this? I want to suggest that the physicist, the chemist, the evolutionary biologist, the psychologist, the sociologist, the historian, the economist can all approach the problems of their fields in exactly the same way. They can make observations, formulate hypotheses and measure the explanatory power of their hypotheses against additional observations. They could do this in ways that would be recognizable to a philosopher who studied such things. But, despite the uniformity of method, the results would be different. The chemist would get things exactly right many times, while the poor economist would be all over the map and often unable to even tell if he was right or wrong.
The difference between chemistry and economics is not primarily in their methods. The difference is in the complexity of their subject matter. What chemists study is pretty trivial—LEGO® -like arrangements of atoms. What economists study is pretty complex—the collective behavior of millions of people with conflicting and uncertain motivations responding to complex stimuli. Nevertheless, both chemistry and economics can make meaningful use of evidence. This is the key point I have been trying to motivate.
A mean-spirited university chemist could certainly heap ridicule on his hapless colleagues in the economics department. “Ha. Ha. You guys have no clue. You just put blind faith in this or that half-baked idea and then hope for the best. Look at my atoms! So neat, so geometrically arranged, so clearly matching the real world. But look at your ideas! So vague, so contradictory, so disconnected from reality.” I think we would all agree that our mean spirited chemist was being unreasonable. His economics colleagues could legitimately respond: “Yes. Of course. Playing with LEGOs® is easy. How fortunate for you that real world chemistry is so much like LEGO®! Now, smash all your LEGO® into powder and build something. Then you will know what economics is like.”
Religious reflection is more like economics than it is like chemistry. There is evidence for the claims of the economist and for the chemist and there is evidence for religious truth claims. This is a simple fact. The New Testament contains several documents written about Jesus by smart people in the first century. These documents are evidence.
One can disagree with the documents and reject the evidence as weak or inadequate in some way. Or one can accept the evidence and be a Christian. But what one cannot do is claim that there is no evidence or dismiss the evidence because it fails to meet the standards of the chemist. If the central claim of Christianity is true—that God became incarnate in Jesus Christ—that is the most complicated and mysterious event in history and the people who tried to articulate what it was like certainly cannot be critiqued because their analyses would not meet the standards of the chemist.
The far more significant difference, of course, relates to the dynamic character of religious investigation. When Isaac Newton “leaped to the conclusion” that gravity ruled the universe, gravity did not respond by embracing Newton and healing his brokenness. When believers make their leap of faith to embrace God, God responds by entering into relationship with believers, often with transformative consequences. There is no counterpart to this response in scientific or historical investigation.
So let’s not disparage the central claims of theology just because they are so much more complicated than the function of penicillin.