The Purpose of this book

The 2 General means for preserving clarity in the search for truth, which will be the subject of this book.

In the previous books, we have seen that man is extremely prone to error; that the illusions of his senses [1], the visions of his imagination [2], and the abstractions of his mind [3] deceive him at every moment; that the inclinations of his will [4] and the passions of his heart [5] almost always conceal the truth from him, and allow it to appear only when it is tinged with those false colors that flatter concupiscence.

I have partly recognized the errors of the mind and the causes of these errors.

I now:

• show the paths that lead to the truth
• give the mind all the strength and skill possible to walk along these paths without tiring itself uselessly or losing its way.

But so that no one takes useless trouble in reading this last book, I believe I should warn that it is made only for those who wish seriously to seek the truth by themselves, and to use for this purpose the proper forces of their own minds.

I ask that they temporarily despise all probable opinions; that they do not linger over the strongest conjectures; that they neglect the authority of all philosophers; that they be, as much as possible, free from prejudice, self-interest, and passion; that they distrust their senses and their imagination greatly; in short, that they remember well most of the things said in the previous books.

The purpose of this last book is to attempt to restore to the mind all the perfection of which it is naturally capable, by providing it with the necessary aids to become more attentive and more comprehensive, and by prescribing the rules that must be observed in the search for truth, so as never to be mistaken, and to learn in time everything that can be known.

If this purpose were carried to its ultimate perfection—which is not claimed, since this is only an essay—one could say that a universal science had been given, and that those who knew how to make use of it would truly be learned, since they would possess the foundation of all particular sciences, and would acquire them in proportion to their use of this universal science. For through this treatise we endeavor to render minds capable of forming true and certain judgments on all questions suited to their capacity.

Just as it is not enough, to be a good geometer, to know by memory all the demonstrations of Euclid, Pappus, Archimedes, Apollonius, and all others who have written on geometry; so too it is not enough, to be a learned philosopher, to have read Plato, Aristotle, Descartes, and to know by memory all their opinions on philosophical questions.

Knowledge of all the opinions and judgments of other men, whether philosophers or geometers, is not so much a science as a history; for true science, which alone can restore to the human mind the perfection of which it is now capable, consists in a certain capacity to judge soundly all things proportionate to it. But so as not to waste time and not to prejudice anyone through hasty judgments, let us begin to treat such an important matter.

We must first recall the rule established and proven at the beginning of the first book, because it is the foundation and first principle of all that we shall say hereafter. I repeat it: one ought never to give full consent except to propositions that appear so evidently true that one cannot refuse consent to them without feeling an inner discomfort and secret reproaches of reason—that is, without clearly recognizing that one would make bad use of one’s freedom by refusing consent. Whenever one consents to probabilities, one certainly puts oneself in danger of being mistaken, and indeed one is almost always mistaken; or finally, if one is not mistaken, it is only by chance and good fortune. Thus the confused view of a great number of probabilities on different subjects does not make our reason more perfect; and only the clear view of truth can give it some perfection and solid satisfaction.

It is therefore easy to conclude that, since only clarity (évidence), according to our first rule, assures us that we are not mistaken, we must above all take care to preserve this clarity in all our perceptions, so that we may judge soundly all things submitted to our reason and discover all truths of which we are capable.

The things that can produce and preserve this clarity are of two kinds. Some are within us or depend in some way on us; others do not depend on us at all. For just as, to see visible objects distinctly, it is necessary to have good eyesight and to fix it steadily upon these objects—two things that are within us or depend on us in some way—so too it is necessary to have a good mind and to apply it strongly to penetrate the depths of intelligible truths—two things that are also within us or depend on us in some way.

But just as the eyes need light to see, and this light depends on external causes, so too the mind needs ideas in order to conceive, and these ideas, as has been proved elsewhere, do not depend on us, but on an external cause that nevertheless gives them to us in consequence of our attention. If it happened, therefore, that the ideas of things were not present to our mind whenever we wished to have them, and if He who enlightens the world wished to hide them from us, it would be impossible for us to remedy this and to know anything; just as it is not possible for us to see visible objects when light is lacking. But this is nothing we need fear, for the presence of ideas in our mind being natural and dependent on the general will of God, which is always constant and unchanging, it never fails us for discovering things that are naturally subject to reason; for the sun that enlightens minds is not like the sun that enlightens bodies; it is never eclipsed, and it penetrates everything without its light being divided.

Since the ideas of all things are thus continually present to us even when we do not consider them attentively, there remains nothing else to do, in order to preserve clarity in all our perceptions, than to seek the means of making our mind more attentive and more comprehensive; just as, to distinguish well the visible objects present to us, it is necessary on our part only to have good eyesight and to consider them steadily.

But because the objects we consider often have more relations than we can discover at once by a simple effort of mind, we still need certain rules that give us the skill to unfold all difficulties so well that, aided by the helps that will make our mind more attentive and more comprehensive, we may discover with complete clarity all the relations of the things we examine.

We shall therefore divide this sixth book into two parts. In the first, we shall treat the aids the mind can use to become more attentive and more comprehensive; and in the second, we shall give the rules it must follow in the search for truths, in order to form solid judgments without fear of being mistaken.