VIII. Orthogonality

In mathematics, two lines or vectors are orthogonal if they meet at right angles (or are perpendicular to one another). I am very fond of this word, as it has a very clear and precise meaning in mathematics (and related subjects such as statistics and the wood working that I do on my table saw in my workshop back in South Carolina).

It also is widely applicable to human affairs, including those things that we can, should, and occasionally do, study in epidemiology. As I like to tell my students, the methods by which (i.e., how) you go about studying whether or not something (like diet) is related to something else (like cancer) is orthogonal to how it works. That is why Bradford Hill and the authors of the Classic 1964 Surgeon General’s Report on Smoking and Health (see chapter VI. Truth or the Water Heater) sought fit to relegate an explanation as to plausibility to dead last among the criteria for judging causality.

Now, don’t get me wrong: I love a good story as much as just about anyone I know. However, I am diligent about building a firewall between the story a priori and the scientific process of discovery. In science, without the truth vector, the story vector really isn’t worth very much. By contrast the truth vector often means a lot all on its own. Take the example of the very first clinical trial in nutrition (or as far as I know, anything else for that matter). Through much of human history, and especially in the northern latitudes, scurvy was a scourge. Conducted in 1754 in sailors in the Royal Navy, Lind’s classic study established that what we later discovered were vitamin C-rich foods could prevent and even reverse scurvy. From then on, as a very practical primary and secondary preventive, sailors were then given limes to keep them healthy (hence the name “Limeys”). Of course, it was another nearly two centuries later that Albert Szent-Györgyi received the Nobel prize (in 1937 just four years after the end of his experiments) for showing ascorbic acid’s critical role in collagen metabolism.

This Fulbright experience is a reminder that orthogonality of events literately punctuates my life (and the lives of many others) in numerous ways. These “chance” meetings in time, space, language and culture provide the clues (indeed the “stuff”) of deeper understanding. I will talk more about these later; much more – because they form the basis for why we are here. After all, these are intersecting universes of experience (though they may seem parallel for long periods of time).