James Hutton's Theory of the Earth: A Machine without a History - Time's Arrow, Time's Cycle: Myth and Metaphor in the Discovery of Geological Time - page 82

the globe, without seeing that progress of things which is brought about in
time. (1788, 296)
We saw in Chapter 2 how Burnet expressed his intricate melding of arrows
and cycles with a corresponding mix of metaphors appropriate for both.
Hutton's metaphors, by contrast, are striking in their exclusivity. He invokes
all the standard-bearers of balance and repetition in our culture, and no
symbols whatever for direction or progress. We have already explored his
primary comparison—a cycling earth with revolving planets of Newton's
cosmos. Hutton's ahistoric world is a dynamic balance of opposing forces,
not a passive stability, and his metaphors record the dynamic steady state of
his cycling system. Thus, planets stay in their orbits because a linear force
that would propel them ever farther away balances a gravitational force that
would pull them into the sun (1788, 212), just as the stability of time's cycle
balances destruction and renovation. Planetary motions also establish a set of
shorter cycles forming abundant material for metaphor: days, seasons, and all
the repetitions described by Hutton under a general rubric of the earth's
fundamental "economy," or balance: "With such wisdom has nature ordered
things in the ceconomy of this world, that the destruction of one continent is
not brought about without the renovation of the earth in the production of
another" (1788, 294).
Most revealing are Hutton's uses of the human body in metaphor, for our
lives, unlike revolving planets, offer abundant material for either arrow or
cycle metaphors. Yet Hutton avoids the obvious directional themes—growth,
learning, development on the one hand; decline, aging, and death on the other
—so avidly embraced by Burnet and other exponents of time's arrow.
Instead, he invokes only those aspects of life that maintain our bodies, or our
populations over generations, in steady state. The circulation of our blood
resembles the hydrologic cycle that erodes continents (Hutton's own doctoral
dissertation as a medical student at Leiden, had treated the circulation of
blood): "All the surface of this earth is formed according to a regular system
of heights and hollows, hills