03/17/2015 11:47 am ET Updated May 17, 2015

Pi and Science, Sense and Cake

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I have been hearing a lot lately about the new documentary, Merchants of Doubt. Of course, I have been hearing from the merchants of doubt for quite some time, as have we all.

A common strategy for their ilk is, on any given topic, is to tell us we need more facts and data before taking any action. But what they really mean is: there is profit in procrastination. The argument that we perennially need to look for more facts before taking action is all too often made by those fully committed to looking away from the actionable facts we have.

Science, much as I love it, is not the best defense against this. We need good science to generate good answers to good questions. We need sense to ask good questions in the first place, and to know when we already know enough. In fact, I can think of only one problem with common sense, really: it's not nearly common enough.

Or rather, it is common -- but familiarity has bred contempt for it. We direct that contempt at one another, and ourselves, and discourage applications of common sense by doing so. The contempt is unwarranted, and the consequences pervasive.

I say so as a career scientist who earns a living by generating, and subjecting to the scrutiny of peer review, scientific data. I like data. But even so, sense deserves respect.

There is no good science without sense, for science only generates the answers to questions sense invites us to ask. There are no good answers to bad questions. Good questions are the progeny of good sense.

We do not need, and cannot have, data to answer every question. We certainly cannot have data that clear some arbitrary methodologic hurdle, such as a randomized controlled trial. Arguments to the contrary abound, but they are often sabotage masquerading as intellectual rigor.

When the beverage industry, for instance, helpfully points out that no long-term, randomized trial has specifically implicated their sugary concoction in epidemic childhood obesity, we might consider that no such trial has ever implicated any given snowflake in an avalanche fatality, either. Perhaps avalanches are actually innocuous.

We have no randomized trials to show that emergency surgery is a better approach to hemorrhaging bullet holes through the chest than watchful waiting, but I suspect that recruiting for trial participants among the next of kin in the Emergency Room would be an unrewarding enterprise. For that matter, we have no randomized trials to show that guns are more effective for -- whatever -- than voodoo dolls; and yet, the NRA never seems to include voodoo dolls in the ramifications of the Second Amendment. Why don't voodoo dolls get attention as the 'arms' to which we are all entitled?

We have no randomized trials to show that if multicolored marshmallows are any part of a 'complete breakfast,' they are the lousy part -- but do we really need any? Do we need randomized trials to confirm that our kids are being manipulated for profit?

And speaking of kids, we have no randomized trials -- to the best of my knowledge -- to show that looking both ways before crossing a street produces better outcomes than closing one's eyes and bolting. And yet, I believe my fellow parents pretty much unanimously favor the "look both ways" approach. Based on what?

Sense. Experience. Both, of the common variety.

Do we know, for instance, the fundamentals of good nutrition? We do. Have they been stable for decades? They have. Do they work to add years to lives and life to years all around the world? They do. Are they in any way associated with one clear winner in our never-ending "my diet can beat your diet" beauty pageant, or the next best-selling fad diet book? They are not.

Is the climate changing? Clearly. Are we implicated in it? Just as clearly. Do we really know? Yes, but more importantly -- who cares?

If we applied the same approach to kids and traffic that many seem inclined to invoke for climate and the environment, we would cite the lack of decisive data, hand our kids blindfolds, and wish them luck. How can we possibly advocate looking both ways before crossing in the absence of all relevant facts?

And yet we do; on the basis of sense. If any climate change deniers out there are equally agnostic about their kids in traffic, I welcome your rebuttal.

For the rest of us, how about we go the other way -- and accept that the right approach to the climate, our diets, and just about everything that matters -- is the one we apply to children near busy streets. When in doubt, do the thing that is most likely to produce a good outcome- based on simple observation, prevailing experience, and common sense.

As the volume of scientific endeavor expands, the pace of publication accelerates, and the representation of every new increment of science in pop culture platforms proliferates, there is ever more opportunity to subordinate ourselves to the tyranny of particular answers, forgetting it was always up to us to decide: what makes a good question?

Some questions can be answered without data. Some answers do not advance understanding. There are no good answers to pointless questions.

I am a scientist. I like science. But it cannot substitute for sense. Those who contend otherwise are trying to sell you something.

National Pi Day, a once-in-a-century landmark, just came and went, and is presumably a reminder to us all of the virtues of science. I am glad to add my "huzzah for Pi!" to the chorus. But I am also tempted to think that maybe cake needs a day, too, in homage to sense.

We have, to my knowledge, no randomized trials to show that it's best to have baked the cake before spreading the icing. And yet bakers the world over have that approach in common- because anything else would be uncommonly senseless, and rather half-baked. I think they are on to something.


David L. Katz, MD, MPH, FACPM, FACP likes having Pi, and eating cake, too.

Director, Yale University Prevention Research Center; Griffin Hospital

Editor-in-Chief, Childhood Obesity

President, American College of Lifestyle Medicine

Founder, The GLiMMER Initiative

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Author: Disease Proof