Author's Note: I initially wrote the following essay about 18 months ago. Recent reader comments inspired me to repost it with a few modifications.

When I was studying philosophy in graduate school, my favorite class was epistemology, or how we know what we think we know.

As philosophers from Aristotle to Wittgenstein have observed, "knowing" something to be true isn't as easy to establish as we often assume it to be. A famous example of how hard it can be to nail down the reality of the physical world was the longstanding argument between Albert Einstein and Niehls Bohr whether quantum mechanics is a complete account of physical reality, or only an incomplete statistical tool. To this day, their argument has never been entirely resolved, though the weight of opinion has shifted to favoring Bohr's intepretation.

The uncertainty of things is especially true in the realm of so-called "medical science." Many make the unexamined assumption that "medical science" is akin to Newtonian mechanics, but this is a gross misconception. The causes of sickness and health—both in individuals and in large populations—are far more complex and multifactorial than than the behavior of solid bodies moving in space.

Consider that while reasonable people often debate about health and disease, none would debate about whether jumping off twenty-story building onto concrete would result in severe injury or death. A complex situation is inevitably riddled with ambiguity and uncertain outcomes and therefore becomes a subject of opposing interpretations and debate.