Darwin, who had such a keen understanding of fruitful procedure in science, knew in his guts that theory and observation are Siamese twins, inextricably intertwined and continually interacting. One cannot perform first, while the other waits in the wings. In mid-career, in 1861, in a letter to Henry Fawcett, Darwin reflected on the false view of earlier geologists. In so doing, he outlined his own conception of proper scientific procedure in the best one-liner ever penned. The last sentence is indelibly impressed on the portal to my psyche.
About thirty years ago there was much talk that geologists ought only to observe and not theorize; and I well remember someone saying that at this rate a man might as well go into a gravelpit and count the pebbles and describe the colors. How odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service!
The point should be obvious. Immanuel Kant, in a famous quip, said that concepts without percepts are empty, whereas percepts without concepts are blind. The world is so complex; why should we strive to comprehend with only half our tools. Let our minds play with ideas; let our senses gather information; and let the rich interaction proceed as it must (for the mind processes what the senses gather, while a disembodied brain, devoid of all external input, would be a sorry instrument indeed).
Yet scientists have a peculiar stake in emphasizing fact over theory, percept over concept—and Darwin wrote to Fawcett to counteract this odd but effective mythology. Scientists often strive for special status by claiming a unique form of “objectivity” inherent in a supposedly universal procedure called the scientific method. We attain this objectivity by clearing the mind of all preconception and then simply seeing, in a pure and unfettered way, what nature presents. This image may be beguiling, but the claim is chimerical, and ultimately haughty and divisive. For the myth of pure perception raises scientists to a pinnacle above all other struggling intellectuals, who must remain mired in constraints of culture and psyche.
But followers of the myth are ultimately hurt and limited, for the immense complexity of the world cannot be grasped or ordered without concepts. “All observation must be for or against some view if it is to be of any service.” Objectivity is not an unobtainable emptying of mind, but a willingness to abandon a set of preferences—for or against some view, as Darwin said—when the world seems to work in a contrary way. [148-9]