To this Rule belongs that of _Dividing the Subject of our Meditations into as many Parts, as we can, and as shall be requisite to Understand it perfectly_. This is indeed most necessary in difficult Questions, which will scarce be unravell’d but in this manner by Pieces: Ever taking care to make Exact Reviews, and to Sum up our Evidence justly e’re we pass Sentence and fix our Judgment. _Rule_ V. To which purpose we must _Always keep our Subject Directly in our Eye, and Closely pursue it thro all our Progress_; there being no better Sign of a good Understanding than Thinking Closely and Pertinently, and Reasoning dependently, so as to make the former part of our Discourse a support to the Latter, and _This_ an Illustration of _That_, carrying Light and Evidence in ev’ry step we take. The neglect of this Rule is the Cause why our Discoveries of Truth are seldom Exact, that so much is often said to so little purpose; and many Intelligent and Industrious Readers when they have Read over a Book are very little wiser than when they began it. And that the two last Rules may be the better observ’d, ’twill be fit very often to look over our Process so far as we have gone, that so by rendring our Subject Familiar, we may the sooner arrive to an Exact Knowlege of it. _Rule_ VI. All which being done we are in a fair way towards keeping the last Rule, which is, _To judge no further than we Perceive, and not to take any thing for Truth which we do not evidently Know to be so_. Indeed in some Cases we are forc’d to content our selves with Probability, but ’twere well if we did so only where ’tis plainly Necessary. That is, when the Subject of our Meditation is such as we cannot possibly have a Certain Knowlege of, because we are not furnish’d with Proofs which have a Constant and Immutable Connexion with the Ideas we apply them to, or because we can’t perceive it, which is our Case in such Exigencies as oblige us to Act presently, on a cursory view of the Arguments propos’d to us, when we want time to trace them to the bottom, and to make use of such means as wou’d discover Truth.