In the seventeenth century, the French philosopher Blaise Pascal looked up at the night sky and then looked down at a mite, picturing “legs with joints, veins in its legs, blood in the veins, humors in the blood, drops in the humors, vapors in the drops,” and onward and downward to the atoms. “The eternal silence of these infinite spaces fills me with dread,” he wrote. He meant two infinite spaces, which he called the two infinites of science, one above and around him, the other below and inside him. Of the two infinites, the space that frightened him more was the space that he could not begin to see, the stardust of atoms that made up his very thoughts and fears and moved the fingers around his pen. “Anyone who considers himself in this way will be terrified at himself.”
The twentieth century was a long spiral inward on Pascal’s path, beginning with a single mutant fly in a milk bottle in the century’s first years, and reaching the atoms that Pascal dreaded to see near the century’s close. If the spiral leads where it now promises or threatens to lead, this may be remembered as one of the most significant series of discoveries since science began, matching the discoveries of twentieth-century physics. In the universe above and around us, physics opened new views of space and time; in the universe below and inside us, biology opened first glimpses of the foundation stones of experience: time, love, and memory.
What are the connections, the physical connections, between genes and behavior? What is the chain of reactions that leads from a single gene to a bark, or a laugh, or a song, or a thought, or a memory, or a glimpse of red, or a turn toward a light, or a raised hand, or a raised wing? The first scientists to look seriously at this question were the revolutionaries who figured out what genes are made of atom by atom–the founders of the science now known as molecular biology. Seymour Benzer was one of those revolutionaries, and he and his students took the enterprise farthest. Benzer’s work on the problem was quiet, his students’ work was quiet, and their story has never been told. But to a large extent the hard science of genes and behavior came out of their fly bottles. In this sense the fly bottle is one of the most significant legacies that the science of the twentieth century bequeaths to the twenty-first, a great gift and disturbance that human knowledge conveys to the night thoughts and day-to-day life of the third millennium. Pascal quoted Saint Augustine: “The way in which minds are attached to bodies is beyond our understanding, and yet this is what we are.”
