James Hutton : biography
It was not merely the earth to which Hutton directed his attention. He had long studied the changes of the atmosphere. The same volume in which his Theory of the Earth appeared contained also a Theory of Rain. He contended that the amount of moisture which the air can retain in solution increases with temperature, and, therefore, that on the mixture of two masses of air of different temperatures a portion of the moisture must be condensed and appear in visible form. He investigated the available data regarding rainfall and climate in different regions of the globe, and came to the conclusion that the rainfall is regulated by the humidity of the air on the one hand, and mixing of different air currents in the higher atmosphere on the other.
Earth as a living entity
The idea that the Earth is alive is found in philosophy and religion, but the first scientific discussion was by James Hutton. In 1785, he stated that the Earth was a superorganism and that its proper study should be physiology.
Although his views anticipated The Gaia hypothesis, proposed in the 1960s by scientist James Lovelock, his idea of a living Earth was forgotten in the intense reductionism of the 19th century.
Hutton also advocated uniformitarianism for living creatures tooevolution, in a senseand even suggested natural selection as a possible mechanism affecting them:
- "…if an organised body is not in the situation and circumstances best adapted to its sustenance and propagation, then, in conceiving an indefinite variety among the individuals of that species, we must be assured, that, on the one hand, those which depart most from the best adapted constitution, will be the most liable to perish, while, on the other hand, those organised bodies, which most approach to the best constitution for the present circumstances, will be best adapted to continue, in preserving themselves and multiplying the individuals of their race."Investigation of the Principles of Knowledge, volume 2.
Hutton gave the example that where dogs survived through "swiftness of foot and quickness of sight… the most defective in respect of those necessary qualities, would be the most subject to perish, and that those who employed them in greatest perfection… would be those who would remain, to preserve themselves, and to continue the race". Equally, if an acute sense of smell were "more necessary to the sustenance of the animal… the same principle [would] change the qualities of the animal, and.. produce a race of well scented hounds, instead of those who catch their prey by swiftness". The same "principle of variation" would influence "every species of plant, whether growing in a forest or a meadow". He came to his ideas as the result of experiments in plant and animal breeding, some of which he outlined in an unpublished manuscript, the Elements of Agriculture. He distinguished between heritable variation as the result of breeding, and non-heritable variations caused by environmental differences such as soil and climate.
Though he saw his "principle of variation" as explaining the development of varieties, Hutton rejected the idea of evolution originating species as a "romantic fantasy". As a deist, he thought the mechanism allowed species to form varieties better adapted to particular conditions and was evidence of benevolent design in nature. Studies of Charles Darwin’s notebooks have shown that Darwin arrived separately at the idea of natural selection which he set out in his 1859 book On the Origin of Species, but it has been speculated that he may have had some half-forgotten memory from his time as a student in Edinburgh of ideas of selection in nature as set out by Hutton, and by William Charles Wells and Patrick Matthew who had both been associated with the city before publishing their ideas on the topic early in the 19th century.