In the first Part, we looked at the prescient writing of the Victorian novelist, Samuel Butler. Butler was way ahead of his age insofar as he was able to apply the theory of evolution—which was still controversial—to the world of the machines. He was able to reach his conclusions because he had abandoned the theory of Vitalism. A few words are therefore necessary to explain Vitalism.
The theory held that there was a qualitative difference between the matter constituting the non-living world e.g. rocks, atmospheric gases, water etc., and the matter constituting the living world of flowers, fish, birds and humans. This was due to a unique property of living matter which created the phenomenon of life. If Vitalism was correct, then there was no possible bridge between the Non-Living and Living worlds. One cannot be turned into the other in the direction of Non-Living turning into Living (although it is obviously possible in the other direction.) Thus, machines—being clearly part of the Non-Living sphere—could never do anything other than mimic certain aspects of the Living, and only then under direction by Living creatures. In other words, they could never be “autonomous.”
Of course, Vitalism is inconsistent with the observed history of life on Earth, which must have had a beginning in the Non-Living realm. One way around this, is the theory of “Panspermia” which states that life is eternal and migrates from star to star, establishing itself on non-living worlds and transforming them into living worlds. This theory was first proposed by the Classical Greek philosopher Anaxagoras in the 5thCentury BCE. It was taken up again after the Enlightenment by thinkers such as Sales-Guyon de Montlivault who in 1821 suggested that Earth had been seeded by bacteria from the Moon. The theory then passed to notable scientists such as Berzelius and Lord Kelvin, finally reaching its status as a testable scientific hypothesis with the work of the chemist Svante Arrhenius. After falling out of favour, it reappeared with the work of Fred Hoyle and Chandra Wickramasinghe in the Twentieth Century, who proposed that pandemics come from close encounters with comets. However, Panspermia cannot be correct in its strictest sense, as the Universe itself is not eternal. Therefore, there must have been at least one instance of matter crossing the Non-Living/Living barrier. If so, it is irrelevant as to which planet was the one where biology began.
However, the first non-theoretical blow to Vitalism was made by the German scientist Friedrich Wöhler (1800-82). In 1828 Wöhler converted the compound ammonium cyanate, known only from non-living sources, into its isomer—urea, known only from living sources. Wöhler himself realised the importance of his work when he wrote: “I must tell you that I can make urea without the use of kidneys of any animal, be it man or dog.”
The combination of theoretical objections and practical experiments effectively disposed of Vitalism as a tenable theory, although some have seen its survival in Henri Bergson’s Élan vital in the Twentieth Century.
However, this refutation was a “vital” step in the growing realisation that there is no uncrossable barrier between Non-Living and Living matter, and that therefore there is no reason to suppose that life and intelligence based ultimately on organic chemistry will be always superior to other forms of organisation in the future.