Question

Lyell's theory that geological processes occurred over time led Darwin to formulate which of these concepts?

Answer 1

By the early 19th century, many people were studying geologic topics, although the term geologist was not yet in general use. Scientists, such as Scottish geologist Charles Lyell, and French geologist Louis Constant Prevost, wanted to establish geology as a rational scientific field, like chemistry or physics. They found this goal to be a challenge in two important ways. First, some people wanted to reconcile geology with the account of creation in Genesis (a book of the Old Testament) or wanted to use supernatural explanations for geologic features. Second, others, such as French anatomist Georges Cuvier, used catastrophes to explain much of earth’s history. In response to these two challenges, Lyell proposed a strict form of uniformitarianism, which assumed not only uniformity of laws but also uniformity of rates and conditions. However, assuming the uniformity of rates and conditions was incorrect, because not all processes have had constant rates throughout time. Also, the earth has had different conditions throughout geologic time—that is, the earth as a rocky planet has evolved. Although Lyell was incorrect to assume uniformity of rates and conditions, his well reasoned and very influential three-volume book, Principles of Geology, was published and revised 11 times between 1830 and 1872. Many geologists consider this book to mark the beginning of geology as a professional field