I had a little studyed, being young, of the parts of Philosophy, Logick, and of the Mathematicks, the Analysis of the Geometricians, and _Algebra_: Three arts or sciences which seem'd to contribute somewhat conducing to my designe: But examining them, I observ'd, That as for Logick, its Sylogisms, and the greatest part of its other Rules, serve rather to expound to another the things they know, or even as _Lullies_ art, to speak with judgment of the things we are ignorant of, then to learn them. And although in effect it contain divers most true and good precepts, yet there are so many others mixed amongst them, either hurtfull or superfluous, That it's even as difficult to extract them, as 'tis to draw a _Diana_ or a _Mercury_ out of a lump of Marble, which is not yet rough-hewn; as for the Analysis of the Ancients, and the _Algebra_ of the Moderns; besides that, they extend only to matters very abstract, and which seem to be of no use; The first being alwayes so tyed to the consideration of figures, That it cannot exercise the understanding, without very much tiring the imagination. And in the latter they have so subjected themselves to certain Rules and cyphers, that they have made a confus'd and obscure art which perplexeth the minde, in stead of a Science to instruct it. For this reason, I thought I ought to seek some other Method, which comprehending the advantages of these, they might be exempt from their defects. And as the multitude of Laws often furnisheth excuses for vice; so a State is fair better polic'd, when having but a few, they are very strictly observ'd therein: So, instead of the great many precepts whereof Logick is compos'd, I thought these four following would be sufficient for me, if I took but a firm and constant resolution not once to fail in the observation of them. The first was, never to receive any thing for true, but what I evidently knew to be so; that's to say, Carefully to avoid Precipitation and Prevention, and to admit nothing more into my judgment, but what should so clearly and distinctly present it self to my minde, that I could have no reason to doubt of it. The second, to divide every One of these difficulties, which I was to examine into as many parcels as could be, and, as was requisite the better to resolve them. The third, to lead my thoughts in order, beginning by the most simple objects, and the easiest to be known; to rise by little and little, as by steps, even to the knowledg of the most mixt; and even supposing an Order among those which naturally doe not precede one the other. And the last, to make every where such exact calculations, and such generall reviews, That I might be confident to have omitted Nothing.