I remember reading one of Richard Dawkins' books in which he made the comment that a rainbow does not become any less beautiful just because we understand how it's formed. Now I've come across a similar statement in another book (The Single Helix) by one of my favourite science writers, Steve Jones.
The Single Helix is a collection of short essays on a very wide range of topics. In one of these essays (The sensitive prince), Jones talks about research into how plants respond to their environment. Such research dates back quite some time, and you'll be familiar with work on phototropism, something which fascinated Charles Darwin. In fact, Darwin not only carried out those elegant experiments into phototropism, but also spent a fair bit of time playing the bassoon to his plants - he wanted to know if they were as sensitive to sound as they were to touch. (They weren't.)
It turns out that plants' responses to things like touch and gravity are governed by a number of gene 'families' that operate in something of a layered manner, affecting growth, cell adhesion, and leaf fall in autumn. And similar genes act in animals (e.g. those coding for calmodulins, which sense calcium levels in our cells & feed this information on to an array of other proteins). Jones says of this nuanced complexity:
But is there not something magical about such layers of scientific rationalism - about how calmodulins connect bassoons with bonsai and the patter of rain with the beat of the heart? Why turn to mere romance in the search for a guiding hand?
Plenty of romantics agree. Shelley writes of a garden in which a mimosa droops in response to a rejected lover's despair: 'Whether the sensitive Plant, or that / Which within its boughs like a Spirit sat / Ere its outward form had known decay, / Now felt this change, I cannot say.'
Biology will never answer Shelley's questions or others like it, but the poet himself saw that science told us things about the world that poetry cannot. He filled his Oxford room with crucibles, chemicals and electrical gadgetry (which hints at why his sister wrote a book so useful to foes of Frankenstein foods) and saw no contradiction between the world of the spirit and the universe of science. He would, no doubt, have been delighted to learn that cooling passions are indeed linked to falling leaves.
S. Jones (2005) The Single Helix. Abacus.