He was awarded the chair of natural philosophy (physics) at the University of Aberdeen's King's College in 1834. In the Disruption of 1843 he left the established Church of Scotland to join the Free Church. In 1845, he became professor of natural history at the Free Church's New College in Edinburgh. He was three times elected president of the Edinburgh Botanical Society (1847–48, 1849–50 and 1856–57).[5] He was then living at 22 Walker Street in Edinburgh's West End.[6]
He died at home, Seagrove House in Leith[7] and is buried with his family in the western half of Dean CemeteryinEdinburgh. He is buried with his wife, Melville Christie (1796–1862) and son Andrew Fleming (1821–1901) (also a fellow of the Royal Society of Edinburgh) who rose to be Depute Surgeon General of the Indian Army.
Fleming was a vitalist who was strongly opposed to materialism. He believed that a 'vital principle' was inherent in the embryo with the capacity of "developing in succession the destined plan of existence."[8] He was a close associate of Robert Edmond Grant, who considered that the same laws of life affected all organisms.
In 1824, Fleming became involved in a famous controversy with the geologist William Buckland about the nature of the flood as described in the Bible. In 1828, he published his History of British Animals. This book addressed both extant and fossil species. It explained the presence of fossils by climate change, suggesting that extinct species would have survived if weather conditions had been favorable. These theories contributed to the advancement of biogeography and exerted some influence on Charles Darwin. Flemings' comments on instinct in his book Philosophy of Zoology had influenced Darwin.[9]
In 1831, Fleming found some fossils which he recognized as fish in the Old Red Sandstone units at Fife. This did not fit the generally accepted notion that the Earth was approximately 6,000 years old.
1821: InsectainSupplement to the fourth, fifth and sixth editions of the Encyclopae-dia Britannica, with preliminary dissertations on the history of the sciences
^Richards, Robert J. (1987). Darwin and the Emergence of Evolutionary Theories of Mind and Behavior. University of Chicago Press. pp. 103-104. ISBN0-226-71200-1
