Ixxvi REPORT—1874. 
his own identity was sure to him; and the development of this system would 
have led to an idealism in which the outer world would be resolved into a 
mere phenomenon of consciousness. Gassendi, one of Descartes’s contem- 
poraries, of whom we shall hear more presently, quickly pointed out that the 
fact of personal existence would be proved as well by reference to any other 
act as to the act of thinking. I eat, therefore I am; or I love, therefore I 
am, would be quite as conclusive. Lichtenberg showed that the very thing 
to\be proved was inevitably postulated in the first two words, “ I think ;” and 
that no inference from the postulate could by any possibility be stronger 
than the postulate itself. 
But Descartes deviated strangely from the idealism implied in his funda- 
mental principle. He was the first to reduce, in a manner eminently capable 
of bearing the test of mental presentation, vital phenomena to purely mecha- 
nical principles. Through fear or love, Descartes was a good churchman ; he 
accordingly rejects the notions of an atom, because it was absurd to suppose 
that God, if he so pleased, could not divide an atom; he puts in the place 
of the atoms small round particles and light splinters, out of which he builds 
the organism. He sketches with marvellous physical insight a machine, with 
water for its motive power, which shall illustrate vital actions. He has made 
clear to his mind that such a machine would be competent to carry on the 
processes of digestion, nutrition, growth, respiration, and the beating of 
the heart. It would be competent to accept impressions from the external 
sense, to store them up in imagination and memory, to go through the internal 
movements of the appetites and passions, the external movement of limbs. 
He deduces these functions of his machine from the mere arrangement of 
its organs, as the movement of a clock or other automaton is deduced from 
its weights and wheels. “As far as these functions are concerned,” he 
says, ‘It is not necessary to conceive any other vegetative or sensitive soul, 
nor any other principle of motion or of life, than the blood and the spirits 
agitated by the fire which burns continually in the heart, and which is in 
nowise different from the fires which exist in inanimate bodies. Had Des- 
cartes been acquainted with the steam-engine, he would have taken it, instead 
of a fall of water, as his motive power, and shown the perfect analogy which 
exists between the oxidation of the food in the body and that of the coal in 
the furnace. He would assuredly have anticipated Mayer in calling the 
blood which the heart diffuses, “the oil of the lamp of life ;” deducing all 
animal motions from the combustion of this oil, as the motions of a steam- 
engine are deduced from the combustion of its coals. As the matter stands, 
however, and considering the circumstances of the time, the boldness, clear- 
ness, and precision with which he grasped the problem of vital dynamics 
constitute a marvellous illustration of intellectual power*. 
During the Middle Ages the doctrine of atoms had to all appearance 
vanished from discussion. In all probability it held its ground among sober- 
minded and thoughtful men, though neither the church nor the world was 
prepared to hear of it with tolerance. Once, in the year 1348, it received 
distinct expression. But retraction by compulsion immediately followed ; 
and thus discouraged, it slumbered till the 17th century, when it was revived 
by a contemporary and friend of Hobbes of Malmesbury, the orthodox 
Catholic provost of Digne, Gassendi. But before stating his relation to the 
Epicurian doctrine, it will be well to say a few words on the effect, as regards 
science, of the general introduction of monotheism among European nations. 
* See Huxley’s admirable Essay on Descartes. Lay Sermons, pp. 364, 365. 
