137 $7. The true Method of advancing Knowledge is by confidering our abftract ideas. WE must therefore, if we will proceed as reafon advises, adapt our methods of inquiry to the nature of the ideas we examine, and the truth we fearch after. General and certain truths are only founded in the habitudes and relations of abftract ideas. A fagacious and methodical application of our thoughts, for the finding out these relations, is the only way to discover all that can be put, with truth and certainty, concerning them, into general propofitions. By what fteps we are to proceed in these, is to be learned in the fchools of the mathematicians, who from very plain and eafy beginnings, by gentle degrees, and a continued chain of reafonings, proceed to the discovery and demonftration of truths, that appear at firft fight beyond human capacity. The art of finding proofs, and the admirable methods they have invented for the fingling out and laying in order those intermediate ideas, that demonftratively show the equality or inequality of unapplicable quantities, is that which has carried them fo far, and produced fuch wonderful and unexpected difcoveries; but whether fomething like this, in respect of other ideas, as well as thofe of magnitude, may not in time be found out, I will not determine. This I think I may say, that if other ideas, that are the real as well as the nominal effences of their fpecies, were pursued in the way familiar to mathematicians, they would carry our thoughts farther, and with greater evidence and clearnefs, than poflibly we are apt to imagine. § 8. By which Morality alfo may be made clearer. THIS gave me the confidence to advance that conjecture, which I fuggeft, chap. 3. viz. that morality is capable of demontration as well as mathematics; for the ideas that ethics are converfant about being all real effences, and fuch as I imagine have a difcoverable connection and agreement one with another; fo far as we can find their habitudes and relations, so far we fhall be poffeffed of certain, real and general Book IV. truths; and I doubt not, but if a right method were taken, a great part of morality might be made out with that clearness that could leave to a confidering man no more reason to doubt, than he could have to doubt of the truth of propofitions in mathematics, which have been demonftrated to him. $9. But Knowledge of Bodies is to be improved only by Experience. IN our fearch after the knowledge of fubftances, our want of ideas that are suitable to fuch a way of proceeding, obliges us to a quite different method. We advance not here as in the other (where our abstrad ideas are real as well as nominal effences), by contemplating our ideas, and confidering their relations and correspondences; that helps us very little, for the reafons that in another place we have at large fet down. By which I think it is evident, that fubftances afford matter of very little general knowledge, and the bare contemplation of their abstract ideas will carry us but a very little way in the fearch of truth and cer tainty. What then are we to do for the improvement of our knowledge in fubftantial beings? Here we ate to take a quite contrary courfe; the want of ideas of their real effences fends us from our own thoughts to the things themselves as they exist: Experience bere muft teach me what reafon cannot, and it is by try ing alone that I can certainly know what other qua lities co-exift with thofe of my complex idea, v. g. whether that yellow, heavy, fufible body I call gold be malleable or no, which experience (which way ever it prove in that particular body I examine) makes me not certain that it is fo in all, or any other yellow, beavy, fufible bodies, but that which I have tried; because it is no confequence one way or the other from my complex idea; the neceflity or inconfiftence of malleability hath no vifible connection with the combination of that colour, weight, and fufibili ty in any body. What I have faid here of the nominal effence of gold, fuppofed to confift of a body of fuch a determinate colour, weight and fufibility, will hold true, if malleableness, fixedness, and folubility in aqua regia be added to it. Our reasonings from thefe ideas will carry us but a little way in the certain discovery of the other properties in those males of matter wherein all these are to be found; because the other properties of fuch bodies depending not on thefe, but on that unknown real effence, on which these alfo depend, we cannot by them dif cover the rest; we can go no farther than the fimple ideas of our nominal effence will carry us, which is very little beyond themfelves, and fo afford us but very fparingly any certain univerfal and useful truths; for upon trial having found that particular piece (and all others of that colour, weight and fufibility that I ever tried) malleable, that alfo makes now perhaps a part of my complex idea, part of my nominal effence of gold; whereby, though 1 make my complex idea to which I affix the name gold, to consist of more fimple ideas than before, yet ftill, it not containing the real effence of any fpecies of bodies, it helps me not certainly to know (I fay to know, perhaps it may to conjecture) the other remaining properties of that body, farther than they have a vifible connection with fome or all of the fimple ideas that make up my nominal effence. For example, I cannot be certain from this complex idea, whether gold be fixed, or no; becaufe, as before, there is no neceffary connection or inconfistence to be difcovered betwixt a complex idea of a body, yellow, heavy, fufible, malleable; betwixt thefe, I fay, and fixednefs; fo that I may certainly know, that in whatsoever body these are found, there fixedness is fure to be. Here again for affurance, I must apply myself to experience; as far as that reaches, I may have certain knowledge, but no farther. 10. This may procure us Convenience, not Science. I DENY not but a man, accustomed to rational and regular experiments, fhall be able to fee father into the nature of bodies, and guefs righter at their yet unknown properties, than one that is a stranger to them; but yet, as I have faid, this is but judgment and opi nion, not knowledge and certainty. This way of getting and improving our knowledge in fubflances only by experience and hiftory, which is all that the weaknefs of our faculties in this ftate of mediocrity which we are in in this world can attain to, makes me fufpect that natural philofophy is not capable of being made a science. We are able, I imagine, to reach very little general knowledge concerning the fpecies of bodies, and their feveral properties. Experiments and historical obfervations we may have, from which we may draw advantages of eafe and health, and thereby increase our stock of conveniencies for this life; but beyond this I fear our talents reach not, nor are our faculties, as I guess, able to advance. § 11. We are fitted for moral Knowledge and natural Improvements. FROM whence it is obvious to conclude, that fince our faculties are not fitted to penetrate into the internal fabric, and real effences of bodies, but yet plainly discover to us the being of a God, and the knowledge of ourselves, enough to lead us into a full and clear discovery of our duty and great concernment; it will become us, as rational creatures, to employ those faculties we have about what they are adapted to, and 'follow the direction of nature, where it seems to point us out the way; for it is rational to conclude that our proper employment lies in thofe inquiries, and in that fort of knowledge which is moft fuited to our natural capacities, and carries in it our greatest interest, i. e. the condition of our eternal eftate. Hence I think I may conclude, that morality is the proper fcience and business of mankind in general (who are both concerned and fitted to fearch out their fummum bonum), as feveral arts, converfant about feveral parts of nature, are the lot and private talent of particular men, for the common ufe of human life, and their own partic var fubfiftence in this world. Of what confequence the difcovery of one natural body and its properties may be to human life, the whole great continent of America is a convincing inftance; whofe ignorance in ufeful arts, and want of the greatest part of the conveniencies of life, in a country that abounded with all forts of natural plenty, I think, may be attributed to their ignorance of what was to be found in a very ordinary defpicable ftone, I mean the mineral of iron; and whatever we think of our parts or improvements in this part of the world, where knowledge and plenty feem to vie each with other, yet to any one that will seriously reflect on it, I fuppofe it will appear paft doubt, that were the ufe of iron loft among us, we should in a few ages be unavoidably reduced to the wants and ignorance of the ancient favage Americans, whofe natural endowments and provifions come no way thort of thofe of the most flourifhing and polite nations; fo that he who first made known the use of that one contemptible mineral, may be truly tyled the father of arts, and author of plenty. 12. But must beware of Hypothefis and wrong Principles. I WOULD not therefore be thought to difesteem, or dif fuade the ftudy of nature. I readily agree, the contemplation of his works gives us occafion to admire, revere, and glorify their Author; and if rightly di rected, may be of greater benefit to mankind than the monuments of exemplary charity, that have at so great charge been raifed by the founders of hofpitals and almshouses. He that first invented printing, difcovered the use of the compafs, or made public the virtue and right use of kin kina, did more for the propagation of knowledge, for the fupplying and increase of ufeful commodities, and faved more from the grave, than those who built colleges, work-houfes and hofpitals. All that I would fay is, that we fhould not be too forwardly poffeffed with the opinion or expectation of knowledge, where it is not to be had, or by ways that will not attain it; that we fhould not take doubtful systems for complete fciences, nor unintelligible notions for fcientifical demonftrations. In the knowledge of bodies, we must be content to glean what |