Picturing the Abyss of Time

The world is so complex, and the skills needed to apprehend it so varied, that even the greatest of intellects often needs a partner to supply an absent skill. As many of history's great lovers secured deputies to match physical appearance with the beauty of their poetry (the tragedy of Cyrano, among others), some scientists have needed a Boswell to present brilliant ideas in comprehensible form. James Hutton, whose Theory of the Earth (1795) marks the conventional discovery of deep time in British geological thought, might have occupied but a footnote to history if his unreadable treatise had not been epitomized by his friend, and brilliant prose stylist, John Playfair, in Illustrations of the Huttonian Theory of the Earth (1802).

In a familiar literary passage, Playfair described a great geological discovery that Hutton had showed him in 1788—not a thing so much as an interpretation. Hutton had recognized what we now call an unconformity as the most dramatic field evidence for time's vastness. Playfair described a phenomenon that Hutton would later depict in one of the few illustrations of his treatise, valued and reproduced ever since as a turning point in human knowledge. (It is, for example, the frontispiece both to this chapter—Figure 3.1— and to John McPhee's Basin and Range):

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