Can we imagine ourselves sincerely convinced of the existence of a being, whose nature we know not; who is inaccessible to all our senses; whose attributes, we are assured, are incomprehensible to us? To persuade me that a being exists or can exist, I must be first told what that being is. To induce me to believe the existence or the possibility of such a being, it is necessary to tell me things concerning him that are not contradictory, and do not destroy one another. In short, to fully convince me of the existence of that being, it is necessary to tell me things that I can understand.
18.
A thing is impossible, when it includes two ideas that mutually destroy one another, and which can neither be conceived nor united in thought. Conviction can be founded only upon the constant testimony of our senses, which alone give birth to our ideas, and enable us to judge of their agreement or disagreement. That, which exists necessarily, is that, whose non-existence implies a contradiction. These principles, universally acknowledged, become erroneous, when applied to the existence of a God. Whatever has been hitherto said upon the subject, is either unintelligible, or perfect contradiction, and must therefore appear absurd to every rational man.
19.
All human knowledge is more or less clear. By what strange fatality have we never been able to elucidate the science of God? The most civilized nations, and among them the most profound thinkers, are in this respect no more enlightened than the most savage tribes and ignorant peasants; and, examining the subject closely, we shall find, that, by the speculations and subtle refinements of men, the divine science has been only more and more obscured. Every religion has hitherto been founded only upon what is called, in logic, begging the question; it takes things for granted, and then proves, by suppositions, instead of principles.
20.
Metaphysics teach us, that God is a pure spirit. But, is modern theology superior to that of the savages? The savages acknowledge a great spirit, for the master of the world. The savages, like all ignorant people, attribute to spirits all the effects, of which their experience cannot discover the true causes. Ask a savage, what works your watch? He will answer, it is a spirit. Ask the divines, what moves the universe? They answer, it is a spirit.