felix qui potuit rerum cognoscere causas

by Elio
 

"Happy is he who was able to know the causes of things" is a statement by the Latin poet Virgil (70–19 BCE) that I have carried with me for some years. I don't mean to suggest that I had a classical education, although I might have acquired one had my family not have to flee from my native Italy during WWII (the teaching of Latin started in the second year of my grade school). But the state­ment resonates in the light of what was the dominant thinking during my early days in science and beyond. No question about it, in the ‘50's and ‘60's molecular biology became dominant and its driving force was reductionism. The dictionary says that reductionism is "the practice of analyzing and describing a complex phenomenon in terms of phenomena that are held to represent a simp­ler or more fundamental level, especially when this is said to provide a sufficient explanation." In other words, reductionism could be seen as a search for the "causes of things." For my purpose, the best example of this is the operon model, which explained on a molecular level how E. coli  learns to utilize lactose. So influential was this idea that it guided the attitude for how many other biological phenomena were to be studied and eventually explained. The license to practicing mo­dern biology, it seemed, required being proficient in "operonology." So, what's wrong with this? On the surface, not much. The reductionist approach has led to hugely important discoveries and con­tinues to dominate the biological scene. Its success can be counted among the great scientific triumphs of the age.
 

Duck of Vaucanson. Source

There is, however, some small measure of discomfort with this. Example: I was told that when Francis Crick heard that Arthur Kornberg had purified a DNA poly­me­rase (albeit not THE DNA polymerase), he said something like: "Well, there had to be an enzyme!" Dismissive as this is (and clearly wrongheaded in the light of how much has been learned from nucleic acid enzymology), a small part of me resonates with this attitude. Let me elaborate.
 

There is a certain motif that underlies many of the stu­dies of interesting phenomena that are being unearthed nowadays. A phenomenon, novel or well known, is cho­sen for analysis. Often, based on biochemical and genetic evidence, a specific protein is found to be responsible for major aspects of the phenomenon. The interaction between this protein and others and with nuc­leic acids in both space and in over the time of the cell cycle is then laid bare. The 3-D structure of the protein tells us what parts of the protein are involved and gives hints about its workings. The location of the protein in a living cell is visualized and the significance of this finding scrutinized. Sometimes, such information lends itself to further quantitative analysis, leading to the postu­la­tion of mathematical models with, one hopes, heuristic value.
 

Now, while admiring the elegance and importance of such work, the reductionist asks: "What's next?" Obviously, we should ask for experiments that enlarge our understanding of the scope of the phenomenon under study, but this may not help us descend the ladder of causality. What comes next in the hierarchy of 'causes'? Atoms, subatomic particles? Surely, someone would care, especially among those versed in such matters. But for the rest of us, is this what we started out asking? And, if this may not necessarily be a hugely appealing way to go, which is?