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 63

Students have no trouble grasping this extended inference, and they do
appreciate the point. Harder to convey is the revolutionary concept embedded
in this inferred history, for Hutton's work helped to incorporate it among the
commonplaces of modern thought. The revolution lies in a comparison with
previous geological theories that included no mechanism for uplift and
viewed the history of our planet as a short tale of uninterrupted erosion, as
the mountains of an original topography foundered into the sea. This debate
did not pit biblical idolatry against scientific thinking, as so often
misportrayed; for as I noted in the last chapter, Steno's mechanical view
shared with other seventeenth-century geologies the theme of continuous
erosion as the organizing principle of history.
The pivot of debate was, instead and again, time's arrow and time's cycle.
Hutton, I will argue, did not draw his fundamental inferences from more
astute observations in the field, but by imposing upon the earth, a priori , the
most pure and rigid concept of time's cycle ever presented in geology—so
rigid, in fact, that it required Playfair's recasting to gain acceptability.
Playfair aided Hutton's victory by soft-pedaling the uncompromising and
ultimately antihistorical view of his late and dear friend.
In any case, this picture, and the unconformity that it represents, gains its
cardinal significance as the primary item of direct evidence for time's cycle
and an ancient earth. One can present abundant theory (as Hutton did) for the
role of heat in uplifting strata, but unconformities are palpable proof that the
earth does not decline but once into ruin; instead, by following decay with
uplift, time cycles the products of erosion in a series that shows, in Hutton's
most famous words, "no vestige of a beginning,—no prospect of an
end" (1788, 304).
Hutton's World Machine and the
Provision of Deep Time
James Hutton had the good fortune to live in one of those rare conjunctions
of time and place which, in a world not overpopulated with genius, bring a
critical mass together for common purposes.