The multifaceted nature of time, both cyclical and irreversible, and the many ways time regulates natural phenomena were approached in our museum during the exhibition “Time of nature,” from October 4, 2003 to March 7, 2004. A conference held on the 9th of February, 2009 with the title “Deep Time: From Steno to Darwin” was expressly dedicated to connecting time with evolutionary theory and to celebrating Charles Darwin’s bicentennial (1809–1877). This aimed at establishing a historical connection between the Tuscan geological and paleontological heritage, a large part of which is stored in Florence, with the emergence of the British school of geology in which young Charles Darwin was trained. At the time Darwin published The Origin of Species, the Florence paleontological collections, albeit not central to his theory, were still well known to some of his peer geologists. The conference, mainly aimed at a public of high school students and their teachers, was less a celebration than a debate among philosophers and geologists committed to reconstructing and understanding precise passages in the history of geology. Since the latter is a sector of the history of science that has only recently started to loosen the fetters of traditional Anglocentric accounts (Baker 2008), the conference turned out to be a lively meeting, full of discoveries for the conveners themselves.
To Nicolas Steno (1638–1686), who enriched and ordered the granducal collection of those objects today we call fossils, then called petrifactions, and wrote in Florence his seminal works of 1667 and 1669, the history of our planet was limited to little more than 6,000 years. In Tuscany, Steno saw how to use sedimentary strata to reconstruct history by geometric relationships, freeing it from textual accounts (Cutler 2003). Steno’s stratigraphic principles (“the lowest is the oldest” and others) and his role in demonstrating the organic origin of fossils are still taught today in Earth science courses (Cutler 2003), but what a thrill to come out of the books and face the outcrops where those principles were first conceived! Leading teachers and students along Steno’s footsteps during the fieldtrip connected with the conference and again the following spring, moreover, adds a much-needed connection between the objects closed in a museum and the territory, helping to imaginarily bring fossils out of the drawers and showcases, into the open space of the outcrops where they were collected. For many participants, this resulted in a lasting impression of what geology is and proved a powerful approach to gaining personal experience with the reconstruction of time through fossils and strata. All the participants were “wearing the shoes” of one—Steno—who had not obviously learned from the manuals how to make an anatomy of the earth.
To celebrate the Darwin bicentennial, it was necessary to explain how the measure of prehuman time had been increased by at least three orders of magnitude by Darwin’s immediate predecessors, four orders by the man himself. Without deep time he would have not conceived the slow transition of one life form into another, so deep time has also been presented as the “lost ingredient” of evolutionary theory. Lost because geological time is seldom mentioned in school books as a prerequisite of evolution by natural selection, and also referring to the fact that the importance of Darwin’s geological training has been overly simplified by scholars, until very recently (Herbert 2005; Eldredge 2006; Rudwick 1974, 2008; Dominici and Eldredge 2010). Darwin was the first to devise a practical way to calculate absolute geological time, measuring the Tertiary in tens of millions of years (actually exaggerating it by five times). Telling what happened between the two centuries that separate Steno’s from Darwin’s writings, and how Florentine fossils were instrumental for understanding the vast stretches of time before the advent of man on earth, catalyzed the attention of the public. Some of our fossils were collected in Tuscany and ordered by Giovanni Targioni Tozzetti (1712–1783), the man of trust of the Granduke, one century after Steno, and one who gave a fundamental impulse to the birth of our museum, in 1775 (Cioppi and Dominici 2010). Targioni conceived a system of classification by merging zoological and paleontological collections, presenting fossils as documents that have traveled “innumerable centuries,” bringing us evidences of former life forms. The remains of fossil proboscideans of the Targioni and granducal collections are today presented to the visitors not just for their systematic and stratigraphic value, but also as instrumental to the history of geology (Monechi and Rook 2010). Among these, the remains of Valdarno proboscideans, first interpreted as remains of “giants,” then as Hannibal’s elephants, were interpreted by Targioni and a few of his contemporaries as prehuman animals, opening the way to the work of George Cuvier (1769–1832), who duly came to visit Targioni’s collections and all other paleontological treasures of Tuscany (Rudwick 2005; Cioppi and Dominici 2010). When confronting one of Targioni’s fossils, the visitor is presented with the discovery of prehuman history, and the anatomically grounded evidence that once upon a time large animals had lived here but are now extinct (Rudwick 2005). In this as in other European museums, each specimen tells two stories, history of science and history of the earth (Fig. 1; Cioppi and Dominici 2011).