De Motu: Sive; De Motus Principio Et Natura, Et De Causa Communicationis Motuum
First published in 1721
Editor's Preface To De Motu
This Latin dissertation on Motion, or change of place in the component atoms of the material world, was written in 1720, when Berkeley was returning to Ireland, after he had spent some years in Italy, on leave of absence from Trinity College. A prize for an essay on the “Cause of Motion,” had, it seems, been offered in that year by the Paris Academy of Sciences. The subject suggested an advance on the line of thought pursued in Berkeley's Principles and Dialogues. The mind-dependent reality of the material world, prominent in those works, was in them insisted on, not as a speculative paradox, but mainly in order to shew the spiritual character of the Power that is continually at work throughout the universe. This essay on what was thus a congenial subject was finished at Lyons, and published early in 1721, soon after Berkeley arrived in London. It was reprinted in his Miscellany in 1752. I have not found evidence that it was ever submitted to the French Academy. At any rate the prize was awarded to Crousaz, the well-known logician and professor of philosophy at Lausanne.
The De Motu is interesting biographically as well as philosophically, as a revelation of Berkeley's way of thinking about the causal relations of Matter and Spirit seven years after the publication of the Dialogues. In 1713 his experience of life was confined to Ireland. Now, after months in London, in the society of Swift, and Pope, and Addison, he had observed nature and men in France and Italy. His eager temperament and extraordinary social charm opened the way in those years of travel to frequent intercourse with famous men. This, for the time, superseded controversy with materialism and scepticism, and diverted his enthusiasm to nature and high art. One likes to see how he handles the old questions as they now arise in the philosophical treatment of motion in space, which was regarded by many as the key to all other phenomena presented in the material world.
For one thing, the unreality of the data of sense after total abstraction of living mind, the chief Principle in the earlier works, lies more in the background in the De Motu. Yet it is tacitly assumed, as the basis of an argument for the powerlessness of all sensible things, and for refunding all active power in the universe into conscious agency. Mens agitat molem might be taken as a motto for the De Motu. Then there is more frequent reference to scientific and philosophical authorities than in his more juvenile treatises. Plato and Aristotle are oftener in view. Italy seems to have introduced him to the physical science of Borelli and Torricelli. Leibniz, who died in 1716, when Berkeley was in Italy, is named by him for the first time in the De Motu. Perhaps he had learned something when he was abroad about the most illustrious philosopher of the time. And it is interesting by the way to find in one of those years what is, I think, the only allusion to Berkeley by Leibniz. It is contained in one of the German philosopher's letters to Des Bosses, in 1715. “Qui in Hybernia corporum [pg 491] realitatem impugnat,” Leibniz writes, “videtur nec rationes afferre idoneas, nee mentem suam satis explicare. Suspicor esse ex eo hominum genere qui per Paradoxa cognosci volunt.” This sentence is interesting on account of the writer, although it suggests vague, and perhaps second-hand knowledge of the Irishman and his principles. The name of Hobbes does not appear in the De Motu. Yet one might have expected it, in consideration of the supreme place which motion takes in his system, which rests upon the principle that all changes in the universe may be resolved into change of place.
In the De Motu the favourite language of ideal realism is abandoned for the most part. “Bodies,” not “ideas of sense,” are contrasted with mind or spirit, although body still means significant appearance presented to the senses. Indeed the term idea occurs less often in this and the subsequent writings of Berkeley.
I will now give some account of salient features in the De Motu.