Little did Cuvier know where this work with mammals was going to lead. For during those early days in the 1790s, when they were getting to know one another and their way round the collections in their new departments, a much older museum man was trying out his secretly rehearsed theory of evolution, but this time on some other unfamiliar collections. He had just been ousted from his old work by Geoffroy and so he was trying out his ideas on what he was soon to name the Invertebrata. He was the fifty year old Jean-Baptiste Lamarck (1744-1829) and in the re-organisation of the museum after the revolution he had been promoted from an obscure job in the herbarium to be Professor of Insects and Worms. He was ranked equally with the twenty one year old Geoffroy who was in charge of the much more favoured and higher ranking mammals, and Lamarck’s jealousy meant that their relationship was troubled.
Over the next decade these three men worked hard to clarify their thinking about the evolution of life and their many differences stimulated one another academically, socially and psychologically. But even then their ideas were far from clear or stable. The men and the things they had to say were so different in so many ways that it was difficult to work out whether life in the museum during those years was great fun or sheer horror. Lamarck’s theory was far too old-fashioned for Cuvier’s exact anatomy, which exhibited a logic more associated with the physics of Laplace and others. Lamarck also had a different idea of the time scale involved in life’s history, finding biblical time scales quite acceptable; Cuvier and the geotheorists wanted much more time for their reconstructions of events and the intervening quiet periods.
Of the arguments between the three that are recorded, some were constructive, some trivial. Their different motives were either political or intellectual, and their relationships both loving and hating. Above all there was uncertainty and that brought out elements of distrust. Geoffroy was the only one to look at the development of species, and he seemed to agree with Lamarck about evolutionary change. That started unpleasant arguments with his friend Cuvier and their relationship began to sour. Jean-Baptiste-Pierre-Antoine de Monet, Chevalier de Lamarck, for that was his full name, had held traditional beliefs that all species were fixed entities. That was until his inaugural lecture on May 11th 1800 when he announced his entirely new theory of evolution. He argued that there were two forces at work to enable evolution by acquisition of new characters. One was a causal flow from environment to organism and another the continuous and spontaneous generation of new life from the chemical constituents. It linked the environment and an animal’s or plant’s physiology; it was how characters were acquired. No wonder the new generation of objective scientists disowned Lamarck so strongly. In 1802 Lamarck published his System of Invertebrate Animals and later, in 1809, he presented his famous evolutionary theory in a bigger book entitled Zoological Philosophy. There he gave examples of the environmental adaptations for which he became well-known, that the giraffe lived “in places where the soil is nearly always barren” and this meant that its neck was “lengthened to such a degree that the giraffe … attains a height of six metres.”
Lamarck’s second major statement concerned the hierarchical level at which the main evolutionary change took place. The main groups were phyla or perhaps families and were the permanent steps up the ladder on which he suggested evolution happened.
Only the frills were changed at the species level leading to diversification but to no major new ladder, or side-branch. Lamarck thought that most evolution happened on these side branches of the big tree, on the steps of the ladder which comprised species and genera. Lamarck also made the unusual suggestion that species lacked a clear identity and merged into one another. This was why he used the old ladder of life analogy for large groups of organisms, lineages merging from one species to another, driven by quick environmental changes, not needing anything to become extinct, just for slightly different species to acquire new ways of living as circumstances required. It was more like an escalator than a ladder, with new families or phyla constantly riding up higher to more complex levels. If species and individuals changed then it was on one of these moving steps. Because there was no evidence for any modification to a species, Cuvier rejected Lamarck’s theory of gradual change just as he rejected the idea of evolution generally. Species did not originate, they were created by God as stable designs and once on earth they became victims of the changing environment. Cuvier assumed that climate change was caused by the regular natural revolutions, and the first reaction of a species to stress was to migrate. If that was still intolerable then the species would die out and become extinct, leaving space for a more tolerant form to take its place. It was an elegant and simple idea and it fitted a lot of the evidence. But the origins remained elusive and new species kept springing up. There was no clear explanation of how they came to be.
After the terror, there were some people in French, German and English academic societies who were exhausted, tired of change and pleased to rest a little. They found Lamarck’s suggestion for slow and gradual changes timely, fitting in well with the idea of a steady-state earth on which the boundaries of land and sea stayed the same. It meant that the earth did not have a history, except for the Flood. But this did not apply to species because Lamarck saw them constantly merging, one to the other, up his ladder. In fact, they were in a constant state of flux and never really existed as stable entities. One consequence of this was that geological time-scales had no importance; for him and “for nature, time is nothing”. These ideas were not as silly as they first sounded, though it wasn’t clear whether Lamarck had been quietly working them out through the years or whether they came suddenly, by chance. Lamarck did have a reputation for short preparation before he reached a conclusion in his work, as had happened over the failure of his method of weather predicting. “I am not submitting an opinion, but announcing a fact. I am indicating an order of things that anyone can verify through observation.” Napoleon himself had refused a copy of Philosophie zoologique thinking it was Lamarck’s book about weather forecasting. That was not all, for Lamarck’s reputation was seriously damaged by the criticisms leveled at his science by Cuvier and Geoffroy. In France these doubts were based on the topical scientific values of time, extinction, catastrophic events, and how species related to one another in nature. In Germany, by contrast the reaction was more philosophical. The critics thought that Lamarck was being too objective without much evidence, and was not thinking about any grand scheme for the whole animal and plant kingdoms. In Britain the objections to Lamarck took into account his lack of evidence, and how he seemed to ignore Genesis altogether. He had nothing significant to say about the Flood and all the topical concern about how to explain the large mammal fossils from the Superficial Gravels. As we shall see it was not until after the Origin of Species was published that Lamarck’s views became popular with some biologists, and then as an alternative to natural selection. Strong arguments and opinion usually attract strong reactions. From then on to the end of his life Lamarck’s thin reputation declined and he became isolated, with no friends, no money and bad health. Cuvier’s reputation grew stronger and his work on birds and mammals was published from the 1800s onwards. The German writer and polymath Johann Goethe (1749-1832) became a regular visitor to the Paris museum and though he was proudly representative of the Duchy of Weimar he became fond of airing his views in the less hostile salons of post-revolutionary Paris. He took the opposite line to Cuvier’s objective focus and thought that for far too long it was the physical sciences that had moved on, while the understanding of life’s transmutation (or “evolution” as it was becoming known) was left very much in limbo. In Paris of the early eighteen hundreds it was the turn of the life sciences to impress their own formality and they benefited from this dose of French style administered by a German romantic.
The youngest of the three Paris naturalists, Etienne Geoffroy Saint- Hilaire was a romantic much influenced by the Naturphilosophie of Goethe and his fellow naturalists, looking for general patterns of morphology rather than the particular detail of each species that interested Cuvier. He was a formalist and came up with a ground plan that the Germans called an archetype. He also disagreed with Lamarck’s ladder of life with its single determination to move upwards to greater complexity, with man at the top. Geoffroy looked the other way as well, at embryos, and inside the bodies at organs where he hoped to find some internal clue to the direction of development.