Competing Histories of the Earth

Scientific Naturalism by the 1720s Nature was an ordered system, governed by laws knowable to man. The key problems and questions of natural history were established for investigation. The new science was protected from religious persecution through natural theology. The major contribution of the early Enlightenment was to establish the basic units of the natural system.

Themes and Big Q’s How did 18 th century thinkers respond to the problems established in the previous century? What were the major competing theories of the earth’s history? What were their strengths and weaknesses? How was the concept of “evolution” or “transformationism” developed and used during the Enlightenment?

New Challenges for the 18 th century Geologic Time Scale Earth’s History The Ordering of the Natural World The Problem of Generation (again!) The Problem of Species

Two Case Studies: Linnaeus and Buffon Linnaeus: Swedish- born son of a clergyman. Famous for his classification system. Buffon: French-born son of a nobleman. Famous for his Historie Naturelle, an encyclopedia of natural knowledge.

Carl Linnaeus ( ) “Classification and name giving will be the foundation of our science.” From Systema Naturae (1735) Why was a classification system vital to natural history?

Classification Dilemmas

Linnaeus’ System of Classification Started with a sexual system of classification for plants  start with one obvious characteristic. 1) Classes and orders: recognized similarities in sexual organs of plants (pistils and stamens) 2) Genera and Species: other characteristics 3) Binomial naming system: common name for all species in a genus + specific name for that particular species. *This is an artificial, not a natural system.

The role of exploration Commercial value of new discoveries. Part of imperial project showing the superiority of European culture.

Georges Leclerc, Comte de Buffon ( ) Head of the Jardin du Roi (Royal Garden) in Paris: huge collection of plants, animals and minerals. Historie Naturelle was his attempt to write a comprehensive history of the world and catalogue of all living things-  without recourse to the Divine* Historie included essays outlining his systematic and scientific approach to earth’s history.

Historie Naturelle- Key Ideas Human history was just the last stage of a long history of the earth. Favored Neptunism to explain earth’s geologic history. Rejected Linnaeus system of classification. “Internal Mold” theory of generation. Fixity of species through spontaneous generation. Hints of evolution?

Buffon and evolution This gets tricky! Species (Linnaean sense) descended from common ancestor (genus) and were transformed by local conditions. Looks like evolution! BUT Buffon treated what we call genera as the REAL species and these were fixed by their “internal mold.” These genera arose through spontaneous generation from free organic particles into complex life. * This is NOT evolution in the Darwinian sense. It is the degeneration of an ancestral form.

Ancestral Cat- Species; Spontaneous Generation

Other theories: Great Chain of Being Charles Bonnet, 1764 Great Chain of Being, Renaissance

Other theories: Hybridization A B C B1 B2 Genus B

Other theories: Random and Radical Materialism Denis Diderot argued for a universe in constant flux. Matter spontaneously organized and generated random forms. Only some survived to produce offspring.

Let’s wrap this up- Summary By the end of the 18 th century it was widely acknowledged by natural philosophers that: 1) Man’s history was simply the last stage of a lengthy earth history. 2) The earth’s surface has changed over time. 3) It was possible to organize species into a rational system of classification. The did NOT agree over: 1) The fixity of species: eternal or changeable? 2) The purpose or design of nature: random or designed?

Fin.