"Philosophers used to ask whether we are born with or invent our sense of time. Now we know that we have clocks woven into every one of our cells. Philosophers also used to ask how we know that the sun will rise tomorrow. In a sense we have that answer built into us, too. The clock is a kind of orrery in the heart of every one of our cells, revolving to help us keep time with our world, a model of the cosmos inside our heads that cycles whether we are in or out of sight of the sun. The revolution of the stars and the seasons is written in the turns of our DNA."

“We do not lift a finger without three kinds of information: the information we are getting from our senses at that moment; the information we have gotten from our senses in the past; and the information our ancestors have acquired since life began on Earth—that is, the information that is represented by genes themselves. Evolution is learning. Species store learning in chromosomes the way individuals store learning in their brains and societies store learning in books.”

“One test of a true clock is its ability to keep time through a wide range of temperatures. A clock that speeds up in hot weather and slows down in cold weather is not a clock, although it may make a good thermometer.”

“All times seem special to those who live in them.”

“The rapid accumulation of change is not always progress, and forward motion is not always an advance.”

““Our only real competition for domination of the planet remains the viruses,” the microbiologist Joshua Lederberg once said. “The survival of humanity,” he added, “is not preordained.”

“With the discovery of the clock gene, the sense of time, mysterious for so many centuries, was no longer a mystery that could be observed only from the outside. Now it could be explored as a mechanism from the inside. The discovery implied that behavior itself could now be charted and mapped as precisely as any other aspect of inheritance. Qualities that people had always thought of as somehow floating above the body, apart from the body, as if they belonged to the realm of the spirit and not of the flesh, as if they were supernatural, might be mapped right alongside qualities as mundane as eye pigment.”