chance and blind combinations of atoms, in de la Bretonne’s opinion, was not the cause of transmutation. De la Bretonne argued that all species had developed from more primitive organisms, and that nature aimed to reach perfection. Denis Diderot, chief editor of the Encyclopedia, spent his time pouring over scientific theories attempting to explain rock strata and the diversity of fossils. Geological and fossil evidence was presented to him as contributions to Encyclopedia articles, chief among them “Mammoth,” “Fossil,” and “Ivory Fossil,” all of which noted the existence of mammoth bones in Siberia. As a result of this geological and fossil evidence, Diderot believed that species were mutable. Particularly, he argued that organisms metamorphosized over millennia, resulting in species changes. In Diderot’s theory of transformationism, random chance plays a large role in allowing species to change, develop and become extinct, as well as having new species form. Specifically, Diderot believed that given randomness and an infinite number of times, all possible scenarios would manifest themselves. He proposed that this randomness was behind the development of new traits in offspring and as a result the development and extinction of species. Diderot drew from Leonardo da Vinci’s comparison of the leg structure of a human and a horse as proof of the interconnectivity of species. He saw this experiment as demonstrating that nature could continually try out new variations. Additionally, Diderot argued that organic molecules and organic matter possessed an inherent consciousness, which allowed the smallest particles of organic matter to organize into fibers, then a network, and then organs. The idea that organic molecules have consciousness was derived from both Maupertuis and Lucretian texts. Overall, Diderot’s musings all fit together as a “composite transformist philosophy,” one dependent on the randomness inherent to nature as a transformist mechanism. Erasmus Darwin developed a theory of universal transformation. His major works, The Botanic Garden (1792), Zoonomia (1794–96), and The Temple of Nature all touched on the transformation of organic creatures. In both The Botanic Garden and The Temple of Nature, Darwin used poetry to describe his ideas regarding species. In Zoonomia, however, Erasmus clearly articulates (as a more scientific text) his beliefs about the connections between organic life. He notes particularly that some plants and animals have “useless appendages,” which have gradually changed from their original, useful states. Additionally, Darwin relied on cosmological transformation as a crucial aspect of his theory of transformation, making