Page:The System of Nature.djvu/126

 other ideas than those of breathing, of respiration, of wind. Thus, when it is said the soul is a spirit, it really means nothing more than that its mode of action is like that of breathing: which though invisible in itself, or acting without being seen, nevertheless produces very visible effects. But breath, it is acknowledged, is a material cause; it is allowed to be air modified; it is not, therefore, a simple or pure substance, such as the moderns designate under the name of SPIRIT.

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