THE SHLVASl ADDRESS. 459 
SECTION 4. In the seventeenth century Bacon and 
Descartes, the restorers of philosophy, appeared in snces- 
sion. Differently educated and endowed, their philosophic 
tendencies were different. Bacon held fast to Induction, 
believing firmly in the existence of an external world, and 
making collected experiences the basis of all knowledge. 
The mathematical studies of Descartes gave him a bias 
toward deduction; and his fundamental principle was 
much the same as that of Protagoras, who made the indi- 
vidual man the measure of all things. " I think, therefore 
I am," said Descartes. Only his own identity was sure to 
him; and the full development of this system would have 
led to an idealism, in which the outer world would have 
been resolved into a mere phenomenon of consciousness. 
GLassendi, one of Descartes' contemporaries, of whom we 
shall hear more presently, quickly pointed out that the 
fact of personal existence would be proved as well by refer- 
ence 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, indeed, showed that the very 
thing to be proved was inevitably postulated in the first 
two words, "I think;" and it is plain that no inference 
from the postulate could, by any possibility, be stronger 
than the postulate itself. 
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 marvel- 
ous 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, and 
the external movements of the limbs. He deduces these 
