How Certain is Science?

Rationally Speaking has a great article on the uncertainties in scientific research and what they mean about science. I think a good deal of the problem here is that people expect certainty, and science doesn’t provide this. Occasionally one can get near certainty, but absolute certainty is elusive. On the frontiers of medicine, especially, you’ll find lots of uncertainty.

In the article the problem is dealt with as one of replicability, but I think that in the public’s eyes that amounts to the same thing as certainty. What cannot be replicated isn’t certain.

I was raised in a medical family. My father was a doctor (general practitioner and proud of it), and my mother is a registered nurse. We talked medical things around the dinner table, so I got used to the terminology. One of the things I learned from my father, in particular, was uncertainty. He was fanatical, I believe, about knowing the latest research, yet he emphasized to me the uncertainties of science, especially his science.

That balance between awareness of the uncertainties, and yet full use of the best knowledge we have, is something that escapes many of us. We either want to worship science or deride it. We choose historically to view it as a series of dominant theories overthrown, or a series of triumphs of new knowledge. In fact, those two views are not incompatible.

I recall early in my time in the U. S. Air Force I was referred to the dietitian to straighten out certain numbers having to do with my cholesterol and triglycerides. I would note that I was quite a number of pounds lighter then than I am now, and didn’t look like I had a problem with fat. So I followed some good dietary advice and got the numbers under control.

A few years later at my annual flight physical, I noticed the numbers from my blood test and was disturbed by one of them. (I always looked through all the test results myself. I found them interesting.) At the end of my consultation with the doctor, who had said nothing of this particular number (and I now forget which it was), I mentioned the number and that perhaps I should do something about.

He said, “Oh, that’s no problem, we have new guidance, and the range for your age is …” The new number put me just within the permissible range. Oh! New study. My old numbers from back in training would have fallen within the range he gave me. (I’m telling this all from memory, so don’t hold me to which number of just how far it changed!)

My personal choice at the time was to do a little more diet watching because I was close to the line, and it seemed a good thing to do. In fact, even now, more than 20 years and an unfortunate number of pounds later, my lab results still don’t scare the friendly family doctor.

My point is that even though the science changed, the general idea of what was a good way to live and eat didn’t change all that much. I was able to work with it, and under either set of criteria, I was better off after I did some work on my diet.

I would suggest that it’s important to realize two things simultaneously: 1) Science is not perfect, and in some cases is very imperfect; and 2) Science is still better at all of these pesky fact things than any other approach we have.

In other words, while my doctors may have had some differences of opinion over the precise levels of certain substances in my blood, they were all much better at giving me guidance than someone from times past who might have told me that fat was a sign of good health.

Related articles

• Science is not dead (scienceblogs.com)
• The Decline Effect (theness.com)
• Read this and think about Truth and Science (currentbuzz.org)