We all know that Charles Darwin's five-year voyage aboard HMS Beagle in 1831-1836 planted the seeds that eventually led to his theory of evolution by natural selection. Less well know is his explanation of the atoll islands of the warm Pacific by a combination of volcanic action, erosion, subsidence and coral growth, also inspired by the voyage. On observing the isle of Mauritius on the homeward leg of the circumnavigation, he wrote of the corals:
We feel surprise when travellers tell us of the vast dimensions of the Pyramids and other great ruins, but how utterly insignificant are the greatest of these, when compared to these mountains of stone accumulated by the agency of various minute and tender animals! This is a wonder which does not at first strike the eye or the body, but, after reflection, the eye of reason.This was the great contribution of Hutton, Lyell, and Darwin –- to stretch our imaginations over vast reaches of space and time which human thought had not yet effectually followed. Even today, after two-centuries in which their theories have been extensively confirmed, we struggle to grasp the eons and the light-years, reflexively holding fast to the human-centered cosmic egg of our more ancient ancestors, framed on a human scale.
Divide us, then, into two tribes: those who retreat for comfort and security into the eye of the body, and those, a minority to be sure, who prefer to live in the eye of reason, where microscopic organisms can build mountains that rise out of the sea, where bacteria can evolve into great blue whales, and where galaxies teem in incomprehensible numbers.
Darwin is our teacher -- as the young, insatiably curious observer who devoured everything that presented itself to his bodily eye, and the sedentary philosopher in his study at Downe, who pondered with his mind's eye what it all meant, following his reflections wherever they led, even to a place where the vast majority of his contemporaries were unwilling to go.