2. These parts of knowledge are not always kept distinct or separate. Philosophical investigation may find a place in history, and historical narrative is often necessary in philosophy. Many things in natural philosophy are ascertained and illustrated by mathematical reasoning. Poetical description may contribute to the embellishment of history; as may be seen in many passages of Livy, Tacitus, and other great historians. And true narrative and sound reasoning may in poetry be. both ornamental and useful, as we see in many parts of Paradise Lost. 3. History is referred to memory, because it records what is past, whereof without memory men would have no knowledge. Poetry is the work of fancy or imagination, that is, of the inventive powers of man; which however must be regulated by the knowledge of nature. Philosophy and mathematics are improved and prosecuted by a right use of reason: but there is this difference between them, that to the discovery of mathematical truth reason is alone sufficient; whereas, to form a philosopher, reason and knowledge of nature are both necessary. Mathematics, therefore, though an instrument of philosophy, and an appendage to it, cannot with propriety be called a part of it. 4. Of philosophy different definitions and descriptions have been given, according to the different views which have been taken of it. As improved by Bacon, Boyle, Newton, and other great men, it may now be defined, the knowledge of nature applied to practical and useful purposes. It is useful in these four respects: first, because it exercises, and consequently improves, the rational powers of man: secondly, because it gives pleasure by gratifying curiosity: thirdly, because it regulates the opinions of men, and directs their actions and, fourthly, because it enables us to discover in part the existence and attributes of the Supreme Being, the Creator of all things, who has established those general principles, which are called the laws of nature, and according to which all the phenomena of the universe are produced. : 5. Without some acquaintance with nature, we could not act at all, either in pursuing good, or in avoiding evil; we should not know that fire would burn or food nourish us. In brutes, whose experience, compared with ours, is very limited, the want of this knowledge is supplied, as far as may be necessary for them or beneficial to us, by natural instinct. We discover causes by comparing things together, and observing the relations, resemblances, and connections, that take place among them, and the effects produced by their being applied to one another. And, by comparing several causes together, we may sometimes trace them up to one common cause, or general principle; as Newton resolved the laws of motion into the vis inertie of matter. 6. As all philosophy is founded in the knowledge of nature, that is, of the things that really exist; and as all the things that really exist, as far as we are concerned in them and capable of observing them, are either bodies or spirits, philosophy con. sists of two parts, the Philosophy of Body, and the Philosophy of Spirit or Mind. The latter, which is our present business, has been sometimes called the Abstract Philosophy, because it treats of things abstracted or distinguished from matter; and sometimes it is called Moral Philosophy, on account of its influence on life and manners. It consists, like every other branch of science, of a speculative and a practical part: the former being employed in ascertaining the appearances, and tracing out the laws of nature; the latter, in applying this knowledge to practical and useful purposes. But to keep these two parts always, and entirely distinct, would, if at all practicable, occasion no little inconvenience. 7. The speculative part of the philosophy of mind has been called Pneumatology. It inquires into the nature of those spirits or minds, whereof we may have certain knowledge, and wherewith it concerns us to be acquainted; and those are the Deity and the human mind. Of other spirits, as good and evil angels, and the vital principle of brutes, (if this may be called spirit), though we know that such things exist, we have not from the light of nature any certain knowledge, nor is it necessary that we should. Pneumatology, therefore, consists of two parts, first, Natural Theology, which evinces the being and attributes of the Deity, as far as these are discoverable by a right use of reason; and, secondly, the Philosophy of the Human Mind, which some writers have termed Psychology. We begin with the latter, because it is more immediately the object of our experience.—An Appendix will be subjoined, concerning the immortality and incorporeal nature of the human soul. 8. The mind of man may be improved, in respect, first of action, and secondly, of knowledge. The practical part, therefore, of this abstract philosophy consists of two parts, Moral Philosophy (strictly so called), which treats of the improvement of our active or moral powers; and Logic, which treats of the improvement of our intellectual |
