THE BELFAST ADDRESS 167 



But Descartes deviated strangely from the idealism im- 

 plied in his fundamental principle. He was the first to 

 reduce, in a manner eminently capable of bearing the test 

 of mental presentation, vital phenomena to purely mechan- 

 ical principles. Through fear or love, Descartes was a 

 good churchman; he accordingly rejected the notion 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 mar- 

 vellous physical insight a machine, with water for its mo- 

 tive 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, nutri- 

 tion, growth, respiration, and the beating of the heart. It 

 would be competent to accept impressions from the ex- 

 ternal sense, to store them up in imagination and mem- 

 ory, to go through the internal movements of the appe- 

 tites and passions, and the external movements of the 

 limbs. He deduces these functions of his machine from 

 the mere arrangements 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 vegeta- 

 tive 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 existing in inanimate 

 bodies." Had Descartes been acquainted with the steam- 

 engine, he would have taken it, instead of a fall of water, 

 as his motive power. He would have shown the perfect 

 analogy which exists between the oxidation of the food in 



