Plausibility of the vibrational theory of smell
The vibrational theory of olfaction explains several aspects of odorant detection that theories based purely on receptor binding do not. It provides for additional selectivity through receptors that are tuned to specific vibrational bands of the odorants they bind, and also through the subsequent conduction of electrons across the odorant, presumably by a tunneling mechanism. A lot of people seem like the theory, or at least its main theorist, Luca Turin. Over the years, efforts to prove, or disprove the vibrational theory have progressed through a long series of olfactory touchstones: molecular enigmas like carvone, acetophenone, or benzaldehyde, whose experimentally perceived scent is a seemingly fickle amalgam of various molecular vibrations, mirror images, and isotopes.