equilibrium) to the overturn of entire faunas (catastrophic hypotheses of mass extinction).

Lyell, by the power of his intellect and the strength of his vision, deserves his status as the greatest of all geologists. But our modern understanding is not his, either unvarnished or even predominantly, but rather an inextricable and even mixture of uniformitarianism and catastrophism. Lyell won a rhetorical war, and cast his opponents into a limbo of antiscience, but we have been compelled to balance his dichotomy—because time's arrow and time's cycle both capture important aspects of reality.

Epilogue

Most working scientists are notorious for their lack of interest in history. In many fields, journals more than a decade old are removed from library shelves and relegated to microfiche, to unheated attics, or even to the junkpile.

During the summer of 1972, I met in Woods Hole with three of the best young-Turk paleontologists and ecologists of our day— Dave Raup, Tom Schopf, and Dan Simberloff. We were trying, immodestly to be sure and with limited success as it happened, to find a new approach to the study of life's history. We wanted to break away from a paleontological tradition that we found stultifying—a training that made professionals into experts about particular groups at particular times in particular places, and seemed to discourage any development of general theories that might be expressed in testable and quantitative terms. We decided to work with random models of origin and extinction, treating species as particles with no special properties linked to their taxonomic status or time of flourishing. As we proceeded, we realized that our models bore remarkable similarity in concept to Lyell's method for dating the Tertiary. Indeed, we recognized that his vision of time's stately cycle had become the ground of our proposal. And so, for several hours, four young scientists out to change the world sat around a table and talked about Charles Lyell.