Those who have distinguished the soul from the body, appear only to have distinguished their brain from themselves. Indeed, the brain is the common center, where all the nerves, distributed through every part of the body, meet and blend themselves: it is by the aid of this interior organ that all those operations are performed which are attributed to the soul: it is the impulse, or the motion, communicated to the nerve, which modifies the brain: in consequence, it re-acts, or gives play to the bodily organs; or rather it acts upon itself, and becomes capable of producing within itself a great variety of motion, which has been designated _intellectual faculties_. From this it may be seen that some philosophers have been desirous to make a spiritual substance of the brain. It is evidently nothing but ignorance that has given birth to and accredited this system, which embraces so little, either of the natural or the rational. It is from not having studied himself, that man has supposed he was compounded with an agent, essentially different from his body: in examining this body, he will find that it is quite useless to recur to hypothesis for the explanation of the various phenomena it presents to his contemplation; that hypothesis can do nothing more than lead him out of the right road to the information after which he seeks. What obscures this question, arises from this, that man cannot see himself: indeed, for this purpose, that would be requisite which is impossible; namely, that he could he at one and the same moment both within and without himself: he may be compared to an Eolian harp, that issues sounds of itself, and should demand what it is that causes it to give them forth? It does not perceive that the sensitive quality of its chords causes the air to brace them; that being so braced, it is rendered sonorous by every gust of wind with which it happens to come in contact. When a theologian, obstinately bent on admitting into man two substances essentially different, is asked why he multiplies beings without necessity? he will reply, because _"thought cannot be a property of matter."_ If, then, it be enquired of him, _cannot God give to matter the faculty of thought?_ he will answer, _"no! seeing that God cannot do impossible things!"_ According to his principles, it is as impossible that spirit or thought can produce matter, as it is impossible that matter can produce spirit or thought: it might, therefore, be concluded against him, that the world was not made by a spirit, any more than a spirit was made by the world. But in this case, does not the theologian, according to his own assertion, acknowledge himself to be the true atheist? Does he not, in fact, circumscribe the attributes of the Deity, and deny his power, to suit his own purpose? Yet these men demand implicit belief in doctrines, which they are obliged to maintain by the most contradictory assertions.