have not collected with care all the principles and facts which are actually there." {358} Having thus formalized the question, M. Royer-Collard follows it up with an inquiry as exact as it is profound, of the psychological fact of the perception of the external world which accompanies the fact of sensation: this inquiry leads him to this conclusion: "Sensation has no object; sensation is merely relative to the sentient being; if not perceived, sensation does not exist. But the perception, which affirms an external existence, supposes two things--the mind which perceives, and the object which is perceived; the being that thinks, and the being that is the subject-matter of thought. Just as the sensation is relative to the mind, so is the act of the perception relative to it also, and just so does it suppose the mind; the object, on the contrary, supposes neither the mind nor the mind's perception. {359} The object does not exist because we perceive it; but we perceive it because it exists--because we are endowed with the faculty of perception. In a city inhabited no longer, there remain no sensation, no idea, no judgment; the houses remain, and even the streets, and with them nature, with all nature's laws, which are not suspended in their course. To the universe, the energetic presence of its Creator suffices; it does not require our presence; the absence of spectators would not make it languish; it existed before us, it will exist after us; its reality is independent of us and of our thoughts--it is absolute. The authority which persuades us of this is no less than that of the consciousness itself; it is the authority of the primitive laws of thought, and to man's mind those laws are absolute laws of truth. The same draught may convey the impression of sweetness and of bitterness, because sensation is relative to the variable state of sensibility, and sensibility itself is relative to organization; but the laws of the mind are an immutable standard. {360} The imperfection of knowledge does not render it uncertain, and although it admits of degrees, it does not admit of contradiction. Our limited faculties do not, it is true, perceive all that there is in things; but still, what they do perceive, is in effect there just as they perceive it. ... If a man call upon me to prove this by reasoning, I shall, in my turn, demand of him, too, that he first prove to me by reasoning that reasoning is more convincing than perception; that he at least prove that the memory, without which there is no such thing as reasoning, is a faculty more to be relied upon than those faculties whose testimony they reject.