Imagine yourself as the doctor in charge of a wilderness outpost in 1750.

A number of your troops are beginning to show signs of illness. Some are losing their teeth. Many have bright red patches on different parts of their bodies. What little hair they have left shows a distinct ‘corkscrew’ pattern. Many are too weak to get out of bed. One disease or many?

You’ve seen this before, so you know it’s one disease – scurvy. You also know that many of these men will soon be dead. What you don’t know is that you could save each of them with a wedge of lemon or a serving of cabbage. You just don’t know.

Now imagine yourself as a London physician in 1800.

A group of your patients have complaints that appear quite similar in certain ways, and quite different in others. Some have painful sores covering much of their body. Others have fever, sore throat and enlarged lymph nodes. Still others have arthritis, and what today would be called ulcerative colitis. A few appear to be losing their minds. One disease or many?

You’ve seen enough to know it’s one disease – syphilis. Your prescribed treatment for each is mercury. You instruct your patients to drink mercury – or they rub it on their skin – or you inject it. It seems to work, at least a little, sometimes.

You’re doing the best you can using everything you know. But you’re killing your patients with side effects. What you don’t know is that with just a little ‘yeast extract’ (penicillin) you could cure each patient. You just don’t know.

It’s 1975 now, and you’re a family practitioner in a small New England town.

A number of your patients begin showing unusual symptoms. Several have developed arthritis in multiple joints. Another has sudden and unexpected kidney failure. Others have fever, muscle aches and headaches. One young girl has developed juvenile rheumatoid arthritis. One disease or many? You believe it’s many.

It turns out it’s one disease – Lyme disease. Each of your patients might have been effectively treated with a common antibiotic. But of course you didn’t know that.

No more imagining – it’s 2009 and something is terribly wrong.

Something is making us sick – very sick. The incidence of allergies, asthma and autoimmune disease are skyrocketing, as are rates for heart disease, Alzheimer’s and too many other conditions to list.

Here’s the question: one disease or many?

The obvious answer is that each is different. Of course they are. But many (most? all?) do share one thing in common – the actual cause of the ailment is unknown.

We definitely know a lot of details – and we’re learning more each day. But looking closely, it seems we know a lot of “what” and very little of “why.” We don’t know what’s really going on. We just don’t know.

No one knew that Lyme was one disease, not many, until a surprisingly large number of juvenile arthritis cases started showing up in the small New England towns of Lyme and Old Lyme. That was a clue. But what’s important, it seems to me, is that someone noticed. Someone said, “Hmmm, that’s odd.” That’s the first step, it seems.

“The most important words in science are not “Eureka, I’ve found it!” – but “Hmmm, that’s odd.” – Isaac Asimov.