Evolutionary theory and speculation on the transmutation of one species into another isn’t something that one associates with medieval thought. The Middle Ages were, after all, the age of faith when the world was interpreted according to the Bible and Aristotelian philosophy, both of which stressed the fixity of species. Now it is true that the modern conception of an evolving universe is a uniquely modern worldview, alien to the philosophers and theologians of the Middle Ages. Nevertheless there was an awareness of change in the varieties of plants and animals, which for some, entirely orthodox philosophers and theologians was developed into a theory of micrevolution in which new breeds of animals had evolved from an ancestral type.
Evolutionary ideas had been developed in antiquity. The Greek philosopher Anaximander considered that humans had first evolved from fish. 1 Empedocles similarly believed that the world moved through periods of cosmic separation and differention, and blending and merging similar to the cycles of ‘Big Bangs’ followed by ‘Big Crunches’ proposed by the Oscillating Universe model in modern cosmology. He suggested that in the early universe, the various parts of human and animal anatomy had appeared separately and, through a process of trial and error, had become attached to each other to produce the characteristic modern lifeforms. This process had also generated monsters, which had been unsuited to survive and so died out. 2 Some of these ideas were taken over by the Church Fathers in their interpretation of Genesis. Noting the apparently different accounts of creation in Genesis 1 and 2, St. Augustine drew on the Stoic doctrine of the Seminal Reasons to suggest that God had implanted in matter the latent germs of future organisms, that developed in due course. 3
In the 13th century Albertus Magnus also discussed the appearance of new species through evolution based on the discussions of the ancients, particularly Theophrastus. Albertus believed that the appearance of new species was demonstrated by the domestication of wild plants, and the appearance of wild varieties from formerly domesticated types. Some of these were not the development of new species as such, but merely the actualisation of potential attributes in an earlier variety, such as when rye increased in size over three times and became wheat. He also believed that some species were generated from the corruption of existing forms, such as when a felled oak or beech tree allowed aspens or poplars to spring up in their place. He also believed that new species could be created by grafting. 4 These early speculations on evolution and speciation continued in the next century with the work of Henry of Hesse, who discussed the appearance of new diseases and the new herbs that would be required to treat them. 5 These early discussions of evolution also influenced Giordano Bruno, Francis Bacon, Leibniz and the 18th century evolutionists. 6
Along with the literal interpretation of Genesis, theologians and religious scholars have also interpreted it allegorically since Philo in the 1st century AD. These scholars include St. Thomas Aquinas, who believed that Creation had been instantaneous, and that Genesis laid out the rational, but not temporal order of Creation:
‘If, however, we take these days to denote merely sequence in the natural order, as Augustine holds and not succession in time, there is nothing to prevent our saying … that the substantial formation of the firmament belongs to the second day.’ 7
Aquinas, like the other scholastics, believed that God also worked through secondary causes through the order He had given the cosmos. ‘the orderly teleology of nonconscious agents in the Universe entails the existence of an intelligent Orderer.’ 8 This notion of the universe as subject to and illustrating a divine order was a vital factor in the development of modern science in the 16th century, when scientists investigated the Book of Nature as a similar revelation to the Book of Scripture.
Thus, while the medieval philosophers and theologians did indeed believe in the fixity of types of species, some of them were interested in the possibility that new varieties could appear of existing types. Furthermore, the allegorical approach adopted by some ancient and medieval theologians meant that when Darwinism emerged in the 19th century many Christians were able to reconcile faith with evolution, whilst rejecting the atheistic implications of the theory.
Thus paradoxically evolution as an idea was partly the result of the Christian investigation of a rationally ordered creation, and the medieval discussion of the development of future varieties of existing types can appear very modern. This in itself can challenge the notion that medieval philosophy and theology was primitive and irrelevant to today. It can also lead one to wonder how far modern scientific views of evolution have actually progressed. Although biological knowledge has increased immeasurably since Albertus Magnus’ time, if ID theory is correct and macroevolution cannot be demonstrated, then science has progressed far less in explaining evolution since the Middle Ages than has been claimed.
1. A.C. Crombie, Augustine to Galileo: Science in the Middle Ages – Fifth to Thirteenth Centuries (London, Mercury Books 1959) p. 150; Jonathan Barnes, Early Greek Philosophy (Harmondsworth, Penguin Books 1987), pp. 72-74.
2. Crombie, Augustine to Galileo, p. 150; Barnes, Early Greek philosophy, pp. 179-181.
3. Crombie, Augustine to Galileo, p. 150; Gordon Leff, Medieval Thought: St. Augustine to Ockham (Harmondsworth, Penguin Books 1958) p. 43.
4. Crombie, Augustine to Galileo, p. 150.
5. Crombie, Augustine to Galileo, pp. 150-151.
6. Crombie, Augustine to Galileo, p. 151.
7. Roger Forster and Paul Marston, Reason, Science and Faith (Crowborough, Monarch Books 1999), p. 214.
8. ‘Aquinas’ in Jennifer Speake, ed., A Dictionary of Philosophy (London, Pan 1979), p. 19.