It is rather singular that in the Hebrew, the Greek, and the Latin, the synonymy, or corresponding term for spirit should signify _breath_. The metaphysicians themselves can best say why they have adopted such a word, to designate the substance they have distinguished from matter: some of them, fearful they should not have distinct beings enough, have gone farther, and compounded man of three substances, BODY, SOUL, and INTELLECT. Although the word _spirit_ is so very ancient among men, the sense attached to it by the moderns is quite new: the idea of spirituality, as admitted at this day, is a recent production of the imagination. Neither PYTHAGORAS nor PLATO, however heated their brain, however decided their taste for the marvellous, appear to have understood by spirit an immaterial substance, or one without extent, devoid of parts; such as that of which the moderns have formed the human soul, the concealed author of motion. The ancients, by the word spirit, were desirous to define matter of an extreme subtilty, of a purer quality than that which acted grossly on our senses. In consequence, some have regarded the soul as an ethereal substance; others as igneous matter; others again have compared it to light. DEMOCRITUS made it consist in motion, consequently gave it a manner of existence. ARISTOXENES, who was himself a musician, made it harmony. ARISTOTLE regarded the soul as the moving faculty, upon which depended the motion of living bodies. The earliest doctors of Christianity had no other idea of the soul, than that it was material. TERTULLIAN, ARNOBIUS, CLEMENT of ALEXANDRIA, ORIGEN, SAINT JUSTIN, IRENAEUS, have all of them discoursed upon it; but have never spoken of it other than as a corporeal substance--as matter. It was reserved for their successors at a great distance of time, to make the human soul and the soul of the world _pure spirits_; that is to say, immaterial substances, of which it is impossible they could form any accurate idea: by degrees this incomprehensible doctrine of spirituality, conformable without doubt to the views of those who make it a principle to annihilate reason, prevailed over the others: But it might be fairly asked, if the pretended proofs of this doctrine owe themselves to a man, who on a much more comprehensible point has been proved in error; if, on that which time has shewn was accessible to man's reason, the great champion in support of this dogma was deceived; are we not bound to examine, with the most rigorous investigation, the reasonings, the evidence, of one who was the decided, the proven child of enthusiasm and error? Yet DESCARTES, to whose sublime errors the world is indebted for the Newtonian system, although before him the soul had been considered spiritual, was the first who established that, "_that which thinks ought to be distinguished from matter_;" from whence he concludes rather hastily, that the soul, or that which thinks in man, is a spirit; or a simple indivisible substance.