“Your laws on Acoustics and Optics are defied by the sounds which you hear within yourselves in sleep, and by the light of an electric sun whose rays often overcome you.  You know no more how light makes itself seen within you, than you know the simple and natural process which changes it on the throats of tropic birds to rubies, sapphires, emeralds, and opals, or keeps it gray and brown on the breasts of the same birds under the cloudy skies of Europe, or whitens it here in the bosom of our polar Nature.  You know not how to decide whether color is a faculty with which all substances are endowed, or an effect produced by an effluence of light.  You admit the saltness of the sea without being able to prove that the water is salt at its greatest depth.  You recognize the existence of various substances which span what you think to be the void,—­substances which are not tangible under any of the forms assumed by Matter, although they put themselves in harmony with Matter in spite of every obstacle.

“All this being so, you believe in the results of Chemistry, although that science still knows no way of gauging the changes produced by the flux and reflux of substances which come and go across your crystals and your instruments on the impalpable filaments of heat or light conducted and projected by the affinities of metal or vitrified flint.  You obtain none but dead substances, from which you have driven the unknown force that holds in check the decomposition of all things here below, and of which cohesion, attraction, vibration, and polarity are but phenomena.  Life is the thought of substances; bodies are only the means of fixing life and holding it to its way.  If bodies were beings living of themselves they would be Cause itself, and could not die.

“When a man discovers the results of the general movement, which is shared by all creations according to their faculty of absorption, you proclaim him mighty in science, as though genius consisted in explaining a thing that is!  Genius ought to cast its eyes beyond effects.  Your men of science would laugh if you said to them:  ’There exist such positive relations between two human beings, one of whom may be here, and the other in Java, that they can at the same instant feel the same sensation, and be conscious of so doing; they can question each other and reply without mistake’; and yet there are mineral substances which exhibit sympathies as far off from each other as those of which I speak.  You believe in the power of the electricity which you find in the magnet and you deny that which emanates from the soul!  According to you, the moon, whose influence upon the tides you think fixed, has none whatever upon the winds, nor upon navigation, nor upon men; she moves the sea, but she must not affect the sick folk; she has undeniable relations with one half of humanity, and nothing at all to do with the other half.  These are your vaunted certainties!

“Let us go a step further.  You believe in physics.  But your physics begin, like the Catholic religion, with an act of faith.  Do they not pre-suppose some external force distinct from substance to which it communicates motion?  You see its effects, but what is it? where is it? what is the essence of its nature, its life? has it any limits?—­and yet, you deny God!