STENO AND DEEP TIME

Nicolaus Steno's great achievement was his recognition that the earth has a scientifically interpretable history, but references to the span of time encompassed by that history are rare in his surviving writings. Did Steno have any inkling of “deep time”? The traditional view is that biblical concerns, as typified by James Ussher's chronology, made it impossible for 17th-century thinkers to contemplate a time span beyond a few thousand years. Accordingly, Steno would have necessarily rejected or suppressed the conclusion that geological processes required or implied long periods of time. The work of Rudwick and others in recent years on the influence of Aristotelean eternalism in geology's prehistory suggests that this should be reconsidered. Steno's failure to challenge biblical chronology in his major geological work De Solido is best seen as part of his rhetorical strategy in making a case for the organic nature of fossils, rather than a capitulation to biblical authority. He emphasized elements of the Bible consistent with his controversial theory, rather than those that might undermine it. Steno's geological history of Tuscany shows he that saw earth history as finite, and so rejected eternalism. But other passages in De Solido indicate that he was open to theories of the earth, such as Buridan's, that put no limit on time scale. However, even if he may have been willing to stretch the scale of earth history beyond biblical limits, Steno, like others of his era, assumed that it was co-extensive with human history. So he did not have a concept of deep time in a modern sense of a long span pre-dating human existence.