“Medicine is a science of uncertainty and an art of probability.”

That bit of wisdom is attributed to Sir William Osler, the doctor often referred to as the father of modern medicine. His insight on the subject of health risk can illuminate today’s cell phone safety debate.

People are having a hard time interpreting the recent finding by a World Health Organization panel that cell phones are “possibly carcinogenic.” Some talk of giving up the phones — or at least going to speaker phone-only.

Others chided the WHO panel for not being more specific about the risk. Still others were surprised to learn that the finding was not the result of new information but a conclusion reached after reviewing numerous existing studies.

So have a cup of coffee — which, by the way, is on the same list of possible carcinogens — and accept this for what it is: the sharing of the best health information we have from a body of knowledge that’s constantly growing.

Scientists themselves aren’t sure of the risk. So they’re doing what the best of them do under the circumstances: calling attention to what they do know, and telling cell phone users to use their own judgment from the available science — most of which indicates that if there is a risk, it’s relatively small. Meanwhile, scientists continue to review data, consider new hypotheses.

It’s frustrating to get inconclusive information, but waiting until danger or safety is proven absolutely would be far worse.

Many people stopped smoking, or tried to, long before the danger was proved beyond a doubt.

We’ve seen this sort of nuance from researchers before, and we’ve seen their conclusions change over time. The industrial chemical bisphonel A is an example. Once unconvinced of any danger from BPA, the Food and Drug Administration continued to evaluate data and now wants the plastics industry to stop using the material in baby bottles and infant feeding cups.

The World Health Organization scientists couldn’t say how large or small a risk cell phone radiation may pose. So they classified it in Group 2B out of five possible categories of risk.

Group 1 is the most toxic substances, with proven causes of cancer such as smoking and asbestos high on the list. Group 2A is for probable carcinogens such as creosotes, diesel exhaust and use of sun beds. Group 2B contains the “possibly carcinogenic” threats, placing cell phones in the company of more than 220 chemicals, pesticides and other potential dangers, including that cup of coffee. Group 3 and Group 4 items are considered to be less risky.

The renowned Sir William Osler believed that thoroughness is the most difficult virtue to acquire in the medical field — “but it is the pearl of great price, worth all the worry and trouble of the search.”

Text that to all your cell phone friends.