VI. The principal faculty of the soul, that which constitutes the fundamental part of its being, and serves, as it were, for its intrinsic light, is the understanding. We may define it that faculty or power, by which the mind perceives, and forms ideas of things, in order to come at the knowledge of truth. Truth may be taken here in two significations; either for the nature, state, and mutual relations of things; or for the ideas agreeable to this nature, state, and relations. To have a knowledge therefore of truth, <6> is to perceive things such as they are in themselves, and to form ideas concerning them conformable to their nature.
Principle. The understanding is naturally right.
VII. We must therefore set out with acknowledging as a fixt and uncontestable principle, that the human understanding is naturally right, and has within itself a strength sufficient to arrive at the knowledge of truth, and to distinguish it from error; especially in things wherein our respective duties are concerned, and which are requisite to form man for a virtuous, honourable, and quiet life; provided, however, he employs all the care and attention that lies in his power.
Sense3 and experience concur to convince us of the truth of this principle; which is the hinge, as it were, whereon the whole system of humanity turns. It cannot be called in question, without sapping the foundation, and intirely subverting the whole structure of society; because this would be annulling all manner of distinction between truth and error, and between good and evil; and by a natural consequence of this subversion, we should find ourselves reduced to the necessity of doubting of every thing; which is the highest pitch of human extravagance.
Those who pretend that reason and its faculties are depraved in such a manner, as to be no longer capable of serving as a sure and faithful guide to man, either in respect to his duties, or particularly with regard to religion; do not reflect that they have adopted for the basis of their system, a principle destructive of all truth, and consequently of religion. Thus we see that the sacred scripture, far from <7> establishing any such maxim, assures us,* that when the Gentiles which have not the law, do by nature the things contained in the law; these having not the law, are a law to themselves. Which shew the work of the law written in their hearts, their conscience also bearing witness.
True it is, that a bad education, vicious habits, and irregular passions, may offuscate the mind; and that neglect, levity, and prejudices, precipitate men frequently into the grossest errors in point of religion and morals. But this proves only that men may make a bad use of their reason, and not that the natural rectitude of the faculties is subverted. What we have still to say, concerning this point, will help to set it in a clearer light.4
In what manner perception, attention, and examen, are formed.
VIII. Let us proceed now to a closer inquiry into the operations of the understanding.5 The perception, or view and knowledge of things, is commonly formed by the concurrence of two actions; one from the object, and is the impression which this object makes on us; the other from the mind, and is properly a glance, or simple view of the soul, on the object it is desirous of knowing. But as a first view is not always sufficient, it is necessary that the mind should apply itself for some time to a serious consideration of the object, to the end it may acquire a just knowledge of things, and form thereof exact ideas. This application, with which the soul continues to view the object in order to know it well, is called attention; and if it turns itself different ways, to consider the object on all sides, this is <8> termed examen or inquiry. We may therefore affirm, that the perception or knowledge of things depends intirely, in respect to the mind, on its natural vigor and attention.
Evidence; Probability.
IX. It is by these helps, drawn from his own fund, that man attains at length a clear and distinct knowledge of things, and their relations; as also of ideas, and the conformity of those ideas to their originals; in short, that he acquires the knowledge of truth. We give the name of evidence, to this clear and distinct view of things, and of their mutual relations; a point to which we should be particularly attentive. For this evidence being the essential characteristic of truth, or the sure mark whereby one cannot help distinguishing it, the consequence is, that it necessarily produces such an internal conviction, as forms the highest degree of certainty. It is true that all objects do not present themselves with so strong a light, and that notwithstanding the great care and application a man may use, all that he is frequently able to attain, is only a glimmering light, which, according to its strength or weakness, produces different degrees of probability and seeming truth. But this must be absolutely the case of every being, whose faculties are limited: It is sufficient that man, in respect to his destination and state, is capable of knowing with certainty those things which concern his perfection and happiness; and moreover, that he is able to distinguish between probability and evidence, as also between the different degrees of probability, in order to proportion his assent to those differences. Now a person need but enter never so little into him-<9>self, and reflect on the operations of his mind, to be convinced, beyond any possibility of doubt, that man is really possessed of this discernment.
Of the senses, the imagination, and memory.
X. The senses, taken for the sensitive faculty, the imagination also, and the memory, must be all reduced to the understanding. In fact, the senses, considered in this manner, are nothing else but the understanding itself, as it makes use of the senses and organs of the body, to perceive corporeal objects. The imagination likewise is nothing but the understanding, as it perceives absent objects, not in themselves, but by their images formed in the brain. The memory, in fine, is no more than the understanding, considered as possessed of the faculty of retaining the ideas it forms of things, and capable of representing them to itself whenever there is occasion; advantages that principally depend on the care we take in repeating frequently those ideas.
The perfection of the understanding consists in the knowledge of truth. Two obstacles to this perfection, ignorance and error.
XI. From what has been hitherto said with regard to the understanding, it follows, that the object of this faculty of the soul is truth, with all the acts and means that lead us to it. Upon this supposition, the perfection of the understanding consists in the knowledge of truth, this being the end for which it is designed.
There are two things, among others, opposite to this perfection, ignorance and error, which are two maladies, as it were, of the mind. Ignorance is no more than a privation of ideas or knowledge; but error is a nonconformity or opposition of our ideas to the nature and state of things. Error being therefore <10> the subversion of truth, is much more opposite to it than ignorance, which is a kind of medium between truth and error.
It is to be observed here, that we do not speak of the understanding, truth, ignorance, and error, purely to know what these things are in themselves; our main design is to consider them as principles of our actions. In this light, ignorance and error, though naturally distinct from one another, are generally mixt, as it were, and confounded; insomuch, that whatsoever is said of one, ought equally to be applied to the other. Ignorance is frequently the cause of error; but whether joined or separate, they follow the same rules, and produce the same effect by the influence they have over our actions or omissions. Perhaps, were we to examine into things exactly, error only, properly speaking, can be looked upon as a principle of action, and not simple ignorance, which being nothing more of itself than a privation of ideas, cannot be productive of any thing.
Different sorts of errors. 1. Error of the law, and of the fact. 2. Voluntary and involuntary. 3. Essential and accidental.
XII. There are several sorts of ignorance and error, whose different divisions it is proper for us to observe. 1. Error considered in respect to its object, is either of the law or of the fact. 2. With regard to its origin, ignorance is voluntary or involuntary, error is vincible or invincible. 3. In relation to the influence of the error on a particular affair or action, it is esteemed essential or accidental.
Error is of the law or fact according as people are mistaken either in respect to the disposition of the law, or in regard to a fact that is not sufficiently known.6 For instance, it would be an error of the <11> law, were a prince to suppose himself intitled to declare war against a neighbouring