I remember as a child the surprise I felt when I learned that most medical drugs were discovered by accident. The most famous example, of course, is penicillin, not just because it was so momentous for human health, but also because it was totally unexpected. In a good example of fortune favoring the prepared mind, we give credit to Alexander Fleming for essentially not just throwing away spoiled bacteria cultures, and instead investigating further the ability of a fungus to secrete molecules we now call antibiotics. In a larger sense, though, the actual “discoverer” was an ancestors of the fungus living millions of years ago, that, it an immense stroke of luck, hit the evolutionary jackpot via a random jumble of DNA that encoded the instructions to make penicillin that allowed it to beat back its bacterial foes. The random tinkering of evolution is the real innovator, with Fleming’s accidental discovery coming much later.

In an interesting twist, we have now learned so much about how the world works that some now look askance at this kind of serendipitous discovery, even though it remains vital to finding news drugs even now. Sort of like Thomas Edison, who found thousands of materials that DON’T work as lightbulb filaments, current pharmaceutical companies are running as many molecules as they can lay their hands in “high-throughput screening” for anticancer properties.   A long blog post from Scientific American discusses the prejudice some physicists show towards this mindset, and, to be truthful, chemistry in general, since it is based on:

“a diverse mix of skills that range from highly rigorous analysis to statistical extrapolation, gut feeling and intuition, and of course, a healthy dose of good luck”

That is to say, reductionism has worked so well for physicists that the rules-of-thumb that are employed daily by chemists look shockingly incomplete. Every empirical relationship is calling out for an explanation based on first principles, we say. For example, Newton looked at  Kepler’s Laws, which were really just relationships noted by pouring over decades of astronomical observations, and explained them all by introducing a law of Universal Gravitation. But just as adding a third body, say, a moon, to the system of  the sun and the Earth, vastly increases the complexity, chemistry is similarly a “many body problem” that resists simple equations, even though the principles of physics remain a the bottom of it.

The joke is that, as in some hunter-gatherer societies, the “many” in “many body physics” means more than two.

Some progress has been made in computer simulations – the so called “in silico” experiments – at explaining properties of molecules, but it is important to remain cognizant that for some complex systems, we should count ourselves lucky if we can discern even empirical relationships. In the wake of a financial crisis, that was brought on in large part because too much trust was placed in complicated models, we should remember the example Nassim Taleb brings in Antifragile of the very successful trader in Green Lumber who made large sums of money over many years on the commodity before it realized that he was buying a selling recently cut trees, not wood painted green.

It has been theorized that Medieval Vikings used naturally bifringent calcite crystals called Sunstones to navigate at sea. According to these historians, the Vikings did not need to know anything about the physics of light polarization; with trial and error, they discovered that it was possible to locate the position of the sun on cloudy days using these seemingly magic stones.

In a piece for Slate, Samuel Arbesman wonders if, with the help of computers, we will discover that the Universe contains relationships that will be forever be beyond human ability to comprehend on any level beyond simply finding that they exist. That is, we will never have our elusive “grand theory” of everything. I am not so pessimistic that such a state of affairs is inevitable, but I do think that we need to make sure we strike the right balance between “thinking” and “tinkering.”

On one level, it is true that chemistry is just “applied physics,” although, according to this thinking, one could argue the same for biology, psychology, and history, although I’m sure chaos theory would be invoked long before the conversation got to that.

Let me close with another snip from the Scientific American blog:

“…most of theoretical physics in the twentieth century consisted of rigorously solving equations and getting answers that agreed with experiment to an unprecedented degree. The tremendous success that physics enjoyed in predicting phenomena spread over 24 orders of magnitude made physicists fall in love with precise measurement and calculation. The goal of many physicists was, and still is, to find three laws that account for at least 99% of the universe. But the situation in drug discovery is more akin to the situation in finance described by the physicist-turned-financial modeler Emanuel Derman; we drug hunters would consider ourselves lucky to find 99 laws that describe 3% of the drug discovery universe.”


Author: lnemzer

Assistant Professor Nova Southeastern University

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