I saw what was called "matter," from the star Sirius and the stars of the Milky Way, as distant from Sirius as Sirius is from us, right to the last atom that can be perceived with the microscope, and I am ignorant as to what matter is.
The light which let me see all these beings is unknown to me; I can, with the help of a prism, dissect this light, and divide it into seven pencils of rays; but I cannot divide these pencils; I am ignorant of what they are composed. Light is of the nature of matter, since it has movement and makes an impression on objects; but it does not tend toward a centre like all bodies: on the contrary, it escapes invincibly from the centre, whereas all matter bears towards its centre. Light seems penetrable, and matter is impenetrable. Is this light matter? is it not matter? with what innumerable properties can it be endowed? I am ignorant thereof.
Is this substance which is so brilliant, so swift and so unknown, are these other substances which roll in the immensity of space, eternal as they seem infinite? I have no idea. Has a necessary being, of sovereign intelligence, created them out of nothing, or has he arranged them? did he produce this order in Time or before Time? What even is this Time of which I speak? I cannot define it. O God! Teach me, for I am enlightened neither by other men's darkness nor by my own.
What is sensation? How have I received it? what connection is there between the air which strikes my ear and the sensation of sound? between this body and the sensation of colour? I am profoundly ignorant thereof, and I shall always be ignorant thereof.
What is thought? where does it dwell? how is it formed? who gives me thought during my sleep? is it by virtue of my will that I think? But always during my sleep, and often while I am awake, I have ideas in spite of myself. These ideas, long forgotten, long relegated to the back shop of my brain, issue from it without my interfering, and present themselves to my memory, which makes vain efforts to recall them.
External objects have not the power to form ideas in me, for one does not give oneself what one has not; I am too sensible that it is not I who give them to me, for they are born without my orders. Who produces them in me? whence do they come? whither do they go? Fugitive phantoms, what invisible hand produces you and causes you to disappear?
Why, alone of all animals, has man the mania for dominating his fellow-men?
Why and how has it been possible that of a hundred thousand million men more than ninety-nine have been immolated to this mania?
How is reason so precious a gift that we would not lose it for anything in the world? and how has this reason served only to make us the most unhappy of all beings?
Whence comes it that loving truth passionately, we are always betrayed to the most gross impostures?