Template Theories, the Rule of Parsimony, and Disregard for Irreproducibility—The Example of Linus Pauling’s Research on Antibody Formation

In 1940, Linus Pauling proposed his template theory of antibody formation, one of many such theories that rejected Paul Ehrlich’s selective theory of preformed “receptors” (antibodies), assuming instead a direct molding of antibody shapes onto that of the antigen. Pauling believed that protein shapes—independently of amino acid sequences—determined antibody specificity and biological specificity in general. His theory was informed by his pioneering work on protein structure, and it was inspired by the intuitive “rule of parsimony” and simplicity. In 1942, Pauling published his alleged success in producing specific artificial antibodies through experiments based on his 1940 theory. However, his experiments could not be reproduced by prominent immunochemists at the time, and, later, it became generally accepted that antibody specificity was not generated according to Pauling’s and others’ “instruction” template theories. A citation analysis shows that Pauling’s papers on antibody generation continue to be cited as, among other things, pioneering studies of a chemical technology called “molecular imprinting.” The examples of Pauling and other protein chemists are used in this paper to demonstrate that scientific belief, philosophical concepts, and subjective theory preferences facilitated the occurrence of irreproducibility in immunochemistry and beyond. The article points to long-term consequences for the scientific community if irreproducible results are not acknowledged. It concludes by arguing that despite the risks, e.g., for the occurrence and perpetuation of irreproducible results that they entail, subjectivity and a commitment to scientific convictions have often been pre-requisites for the generation, and holding on to, scientific innovation in the face of doubt and rejection from the scientific community.

Viscosity-enhanced droplet motion in sealed superhydrophobic capillaries

It is well known that an increased viscosity slows down fluid dynamics. Here we show that this intuitive rule is not general and can fail for liquids flowing in confined liquid-repellent systems. A gravity-driven, highly viscous glycerol droplet inside a sealed superhydrophobic capillary is moving more than 10 times faster than a water droplet with three-orders-of-magnitude lower viscosity. Using tracer particles, we show that the low-viscosity droplets are rapidly rotating internally, with flow velocities greatly exceeding the center-of-mass velocity. This is in stark contrast to the faster moving high-viscosity droplets with nearly vanishing internal flows. The anomalous viscosity-enhanced flow is caused by a viscosity-suppressed deformation of the droplet-air interface and a hydro- and aerodynamic coupling between the droplet and the air trapped within the micro/nanostructures (plastron). Our work demonstrates the unexpected role of the plastron in controlling fluid flow beyond the mere reduction in contact area and friction.