It is not surprising, lastly, that these two kinds of knowledge or of certitude should spring up and propagate themselves by different means. Objective science transmits itself by objective demonstration. The subjective life of the savant has nothing to do with it. To convince us of the reality of his discoveries, an astronomer does not need to be a good man. On the contrary, a fundamentally immoral man will always be a detestable professor of ethics. Religion is only propagated by religious men. It may also be added that, in religious knowledge, the intellectual demonstration or the idea has no value except in so far as it serves as the expression and the vehicle of the personal life of the subject. This is the secret and the mystery of eloquence. The _si vis me flere, dolendum_, is true in all the moral disciplines, as much and more than in aesthetics. One gains nothing by attempting to demonstrate objectively the existence of God. That demonstration is ineffective towards those who have no piety; for those who have, it is superfluous. The true religious propaganda is effected by inward contagion. _Ex vivo vivus nascitur_. Accuracy in theology is much less important in religion than warmth of piety. Pitiful arguments have in all ages been followed by admirable conversions. Those who are scandalised at this have not yet penetrated into the essence of religious faith. For want of this clear and frank separation between our two orders of knowledge, one sees, on the one hand, philosophers pretending to transform ethics and philosophy into objective science, and, on the other, savants naively giving forth their objective science as a metaphysic and as a solution of the enigma of life. Two illusions, in whose train everything is mixed up and founded. Objective ethics are everything you could wish--except ethics. You might as well speak of a round square. When an objective science transforms itself into metaphysics, it ceases to be science and becomes subjective philosophy. This goes without saying.