ABSTRACT
While mechanistic explanations are by no means a novelty in biology (see Part I on historical perspectives on mechanisms), their appearance dating back to Harvey’s discovery of the blood’s circulation and Descartes’ mechanistic manifesto touted in The Treatise of Man, it is only in the second half of the twentieth century, with the rise of molecular biology, that mechanistic thinking overtakes the whole of biology, becoming the predominant type of explanation. Explaining biological phenomena as the effects of molecular mechanisms turned out to have a marked influence on philosophy of science on two accounts. First, it motivated a renewed interest in mechanistic explanation, providing philosophers with a wealth of examples that didn’t quite fit the deductive-nomological approach promoted by the logical positivists (Wimsatt 1976). Second, molecular biology motivated a shift in the way we think about mechanisms, fostering a “new” mechanistic philosophy. Unlike the “old” mechanistic philosophy, which was closely linked to the theory of classical mechanics and the clockwork view of the world, the “new” mechanistic philosophy had to come to terms with the notion that most biological mechanisms do not look and behave like eighteenth-century automata, but are much more complex and “noisier” systems composed of hundreds, thousands, and even millions of non-fixed, non-rigid parts whose behavior is nevertheless sufficiently constrained both by the properties of the parts and by the spatio-temporal organizational features of the system as to reliably produce and sustain biological phenomena and, ultimately, life itself.
