It is not enough for a wise man to study nature and truth; he should dare state truth for the benefit of the few who are willing and able to think. As for the rest, who are voluntarily slaves of prejudice, they can no more attain truth, than frogs can fly.
I reduce to two the systems of philosophy which deal with man's soul.
The first and older system is materialism; the second is spiritualism.
The metaphysicians who have hinted that matter may well be endowed with the faculty of thought have perhaps not reasoned ill. For there is in this case a certain advantage in their inadequate way of expressing their meaning. In truth, to ask whether matter can think, without considering it otherwise than in itself, is like asking whether matter can tell time. It may be foreseen that we shall avoid this reef upon which Locke had the bad luck to shipwreck.
The Leibnizians with their monads have set up an unintelligible hypothesis.
They have rather spiritualized matter than materialized the soul. How can we define a being whose nature is absolutely unknown to us?
Descartes and all the Cartesians, among whom the followers of Malebranche have long been numbered, have made the same mistake. They have taken for granted two distinct substances in man, as if they had seen them, and positively counted them.
The wisest men have declared that the soul can not know itself save by the light of faith. However, as reasonable beings they have thought that they could reserve for themselves the right of examining what the Bible means by the word ``spirit,'' which it uses in speaking of the human soul. And if in their investigation, they do not agree with the theologians on this point, are the theologians more in agreement among themselves on all other points?
Here is the result in a few words of all their reflections. If there is a God, he is the Author of nature was well as of revelation.
He has given us the one to explain the other, and reason to make them agree.