“Notice also that scientists generally avoid the use of the word proof. Evidence can support a hypothesis or a theory, but it cannot prove a theory to be true. It is always possible that in the future a new idea will provide a better explanation of the evidence.” — J.E. McLaren and L. Rotundo, in the high school text Health Biology
Proof? You want proof? Then become a mathematician. Math is full of proofs.
But science? No way. We base our modern civilization on science, and yet science cannot prove anything. How can that be so?
Well, as mentioned above, science deals with evidence and theories, not proofs.
Unfortunately, this gives easy brownie points for the scientifically illiterate to dispute environmental problems. They have the audacity to say that there is no proof that a cancer causing chemical coursing through someone’s body has caused their cancer. Or they will contend that there is no proof that lofting a ½ trillion tonnes of carbon dioxide into the atmosphere has anything to do with the warming of the planet.
And you know what? They’d be right. Not because they know anything about science, but because science doesn’t deal with proofs.
Remember high school science class? We watched fungus grow in petri dishes or we built bridge trusses out of Popsicle sticks. But we didn’t prove anything. When we wrote up our findings, we used the headings: theory, hypothesis, observations and conclusions.
Some of us then went on further to tech school or university and took courses in statistics. We called it “sadistics” back then, but aside from the mild torture of having to crunch a bunch of numbers, we did learn a thing or two about evidence and probabilities.
Science uses statistics. And the insurance industry also uses statistics. My insurance provider has no proof that I’ll go out and crash my car or that my house will burn down on any given day. But they have enough common sense to insure me based on probabilities. And somehow we don’t get all twisted in a knot over that. So why do some people get all anti-science when science says that there is a very high probability that we’re over-fishing or that topsoil is disappearing or that carbon dioxide is warming the planet?
A lot of the problem boils down to the complexity of natural systems. A cubic foot of soil or a single cell in your pinky finger is a million times more complex than the math used to send Neil Armstrong to the moon. And some natural systems (like the global atmosphere) can’t be stuffed into a laboratory. Thus, we have the need for evidence and theories and models. Scientists gather evidence and see how well it fits into theories and models.
Perhaps the best analogy to use when thinking about the difference between proof on the one hand and overwhelming evidence on the other, is O.J. Simpson.
Ever stop to think why he got aquitted in the criminal court, but convicted in the civil court? Sure, there was the race-baiting on the part of the defense team, but there was also the simple fact that in a criminal case, proof “beyond a reasonable doubt” is required. In a civil case, by contrast, all that is needed is a “preponderance of evidence”.
So the choice is up to you. When it comes to kind of planet that you want your kids to inherit, are you going to demand absolute proof before you lift a finger? Or will you use common sense and weigh the evidence?
Evan Bedford is a local environmentalist. Direct comments, questions and suggestions to firstname.lastname@example.org. Visit the Energy and Ecology website at www.evanbedford.com.