Fifthly, Civil history, or regular accounts of the transactions of the world politic. To this head must be referred that part of geography which treats of the present manners, customs, laws, religion, &c. of the several nations of the world.
Sixthly, Natural philosophy, or the application of the arts of mathematics and logic to the phænomena of natural and civil history communicated to us by means of our previous skill in philology, in order to decypher the laws by which the external world is governed, and thereby to predict or produce such phænomena, as we are interested in. Its parts are mechanics, hydrostatics, pneumatics, optics, astronomy, chemistry, the theories of the several manual arts and trades, medicine and psychology, or the theory of the human mind, with that of the intellectual principles of brute animals.
Seventhly, Religion, which might also be called divine philosophy. This requires the application of all the foregoing branches of knowledge to each other in an endless reciprocation, in order to discover the nature of the invisible world, of God, of good and evil spirits, and of the future state, which commences at death, with all the duties that result from these considerations. The arts of ethics, and politics, are to be referred to this head. For, though these arts are supposed to teach individuals, and bodies politic, how to arrive at their summum bonum in the present world, yet, since the rules given for this purpose either are or ought to be the same with those which teach mankind how to secure a happy futurity, it is plain, that these arts are included within the precepts of religion.
All these branches of knowledge are very much involved in each other; so that it is impossible to make any considerable progress in any one, without the assistance of most or all the rest. However, each has also an independent part, which being laid down as a foundation, we may proceed to improve it by the light afforded from the independent parts of the other branches. I will here subjoin a few hints concerning the proper manner of proceeding in each branch.
The rudiments of the native language are learnt in infancy, by the repeated impressions of the sounds, at the same time that the things signified are presented to the senses, as has been already explained. Words standing for intellectual things, particles, &c., are decyphered by their connexion with other words, by their making parts of sentences, whose whole import is known. Grammatical analogy and derivation do also, in many cases, discover the import of words. And many words may be explained by definitions. Where these several ways concur, the sense is soon learnt, and steadily fixed; where they oppose each other, confusion arises for a time, but the strongest authority prevails at last. Translations and dictionaries explain the words
