Time's Arrow, Time's Cycle: Myth and Metaphor in the Discovery of Geological Time Book

In this book, Stephen Jay Gould explores two metaphors, two models, that humans use to understand time: time's arrow, the the irreversible, unrepeatable uniqueness of every individual, every event, and every phenomenon, and time's cycle, the fundamental laws and structures that repeat and reappear throughout the universe. This was prompted in his field by the discovery of deep time - of a universe that is not thousands, but rather billions of years old. If the present earth formed over billions of years, how did present structures emerge - as the products of sudden catastrophes or miracles, or as the gradual results of slow, steady change?

In the first chapter, Gould simply posits the scope and intention of his work - he is exploring the development of these metaphors in the writings of 3 British geologists.

In Chapter 2, he explores the Telluris Theoria Sacra of Thomas Burnet. Writing from a theological perspective, Burnet created an image of the earth from the Creation to the End Times, with both parts meeting under Christ's feet.. This captured both the arrow - time flows inexorably as part of salvation history - and the cycle - each stage in the beginning is echoed in a stage at the end. Gould then draws a parallel to the geological work of Nicholas Steno, whose theory for the history of Tuscany has almost the same schema even though his work was more field-based.

In Chapter 3, Gould explores James Hutton's 1795 Theory of the Earth. Hutton's system was based on the belief that not only do objects have material causes (what makes them up) and efficient causes (what event immediately caused the object to exist), but also a final cause/telos (every object has a purpose directed towards human needs). Hutton was confronted with the "paradox of soil" - if soil exists to make the earth productive for human life and agriculture but is produced by a fundamentally destructive process (erosion), then a priori there must be a corresponding creative process to ensure that human civilization continues. For final cause, Hutton insisted that "uplift must restore topography"; "for efficient cause, he devised a world machine that arranged all historical complexity as a cycle of repeating events as regular as the revolution of planets in Newton's system"(p. 79). Because Hutton's universe functions as a perfect balance, it also fundamentally denies history - if things improve, then the system was not perfect; if things get worse, then the system is not perfect. Even fossils are only signs of regional and local variation, not of fundamental biological change - only humans have a special divine creation in the recent past. As Gould notes, this is the most extreme theory of time's cycle in the history of geology.

In Chapter 4, Gould explores the life-work of Thomas Lyell, who was active from the 1820s to the 1870s. Lyell used brilliant rhetoric to promote a theory of uniformitarianism that combined multiple meanings of uniformity. Basically all scientists agreed on uniformity of law (natural laws work the same throughout space and time) and uniformity of process (if a present process can account for a situation, use it instead of trying to imagine some unknown cause as an explanation). To these methodological claims, Lyell added the far more controversial uniformity of rate (processes occur at the same rate throughout history) and uniformity of state (there is no progress or long-term trends in either earth history or biological history, and everything is directionless). Lyell argued that apparent unconformities and rapid changes in biota were due to a lack of preservation, erosion, or other destruction of evidence - there are no catastrophes or mass extinctions. Mammals dominate now because the climate is cooler. If the world were warmer, "The huge iguanadon might reappear in the woods, and the icthysaur in the sea, while the pterodactyl might flit again . . . " (p. 103 - 104). Lyell also proposed that fossil assemblages preserved in sedimentary strata could be relatively dated by comparing their members to the present-day - those more similar to the present would be more recent, and those with fewer modern species would be older. Lyell only admitted to evolution and trends in biology when confronted with decades of paleontological evidence, but still held firm to geological gradualism and directionless evolutionary processes.

Finally, in the conclusion Gould muses on the necessity and aesthetics of both metaphors - time's arrow and time's cycle - for making the natural world comprehensible to humans.

What I love about Gould's writing is how he weaves together so many disciplines - geology, philosophy, history, literary analysis, theology, poetry, the fine arts. I feel like I am walking through a museum, listening to a learned professor or curator reflecting on the themes they are considering (which makes sense, since he was a Harvard professor and curator). Gould weaves these threads together magnificently, and constantly reinforces his thesis throughout the book. I loved the book from beginning to end, and now I want to read more.