The search for the nature of the First Cause--I do not say the “knowledge of God,” which would be an expression worthy of a “theologian” and absurd in itself--but simply the search for the Absolute Being, for the origin of the energy which sustains, animates, and governs the universe, for the intelligent force which acts everywhere and perpetually through infinity and eternity and gives rise to the appearances which strike our eyes and are studied by our science--this _search_, I say, could not be undertaken nor even properly conceived before the first discoveries of astronomy and modern physics, that is to say, before the investigations of Galileo, Kepler, and Newton. It is only two centuries ago that the purely religious idea, free from idolatries, from all sorts of mythologies, of errors and superstitions produced by primitive ignorance--it is only during the last two centuries that it was possible for this idea to arise out of modern scientific evolution. All the religions existing at the present day have been founded during ages of ignorance, when we knew nothing about the earth or the heavens. True religion, i.e. the union of free spirits in the search for truth, can only be the work of an epoch like ours, in which some courageous and disinterested spirits free from the hypocrisy of false doctrines, yet without falling into the puerile atheism of superficial minds which only see the outer shell, will sincerely and freely apply all branches of science to the search for the intimate constitution of the universe and of the human being. The future will teach us. To-day we know but little; we are only beginning to learn. The unknown God conceived by the thinkers, by Socrates, by Plato, by Marcus Aurelius, by Voltaire (as ardent a Deist as he was a violent anticlerical), by Newton, by Descartes, by Linné, by Euler, by Spinoza, by Kant, by all pure Deists, surpasses in his grand immensity all the poor inventions of the clergy of all denominations. One cannot see the creator of the hundred million suns of the Milky Way looking down upon a small village in Judea and inspiring Judith to seduce Holophernes with the object of cutting off his head after betraying him with her caresses; or conferring on Joshua the power of arresting the movement of the solar system to give him time to exterminate the besiegers of Gibeon! What sort of opinion had such writers of the Supreme Being? And what opinion of him is still held by those preachers who continue to teach this “Holy Scripture”? The Infinite cannot be comprehended by the Finite. He who has made the tour of the world, who has visited Europe, Asia, Africa, and the Americas, reasons in a manner wider beyond comparison with the state of humanity than he who has never left his country. Between the narrow, incomplete, and false ideas of the latter and the judicious, exact, and just appreciations of the former there is the difference of night and day.