VIII. Man has many advantages and privileges over all other creatures. Not only can he, like other animals, perceive through his senses all the surrounding objects, but he can compare with one another the perceptions received, associate them together, separate them, and form new ideas. He can know for what purposes things exist, investigate their causes and effects, discern between good and evil, between just and unjust; he alone can communicate his thoughts to others; he alone can speak.

IX. Everything produced by an intelligent Author must be intended for some purpose must have a destination. Man, the noblest creature on earth, must also have a destination. We shall arrive at a clear knowledge of that destination, when we shall have considered the powers and capabilities possessed by him; for the means with which nature has endowed him, for the development of his activity, evidently point out the goal which that activity is designed to attain.

X. Now, the capabilities that we discover in man are the following: Besides a body constructed with wonderful skill, but weak, corruptible, mortal, man has within himself a vivifying principle, which substantiates in him the knowledge of things with the aid of the senses, renews in him perceptions once received, unites them, separates them, and forms out of them new ideas. This thinking principle is certainly different from the body, of which no part is apt to think, and is what we call the soul; the act itself of thinking proceeds from a faculty of the soul which we call intellect.

XI. But the soul can also judge, conclude from causes to effects, distinguish between good and evil, between just and unjust, conceive an idea of things never perceived through the senses; it can recognise the supreme Author of the universe, it can adore God. This faculty of the soul is called reason; intellect and reason are the principal or superior faculties of the human soul.

XII. Reason points out good as a thing desirable, and evil as a thing to be avoided; yet man feels within himself a desire or impulse towards all that is pleasurable to the senses, although reason may represent it to him as an evil. And, on the other hand, he is conscious of his perfect freedom of choosing good, however disagreeable to the senses, and of abhorring evil, however tempting it may appear; he has, then, the faculty of directing his action to one or other of these two courses; his soul is endowed with free-will.

XIII. A being endowed with intellect, reason, and free-will cannot be composed of parts, because the operations proceeding from such faculties presuppose a comparison of various relations with each other, and a deduction of consequences from their principles; and these operations require such a unity and simplicity in their subject as are absolutely incompatible with the nature of matter, composed, as it is, of parts. The human soul is therefore a simple being, a spirit, and, as such, indestructible, immortal.

XIV. Man, then, unites in himself two natures, belongs to two classes of beings very different from one another, is a citizen of two worlds. In his body he is linked to the material world, undergoes all the vicissitudes of matter, is subject to the incentives of the senses, and is impelled to gratify the wants and cravings of physical enjoyment. As regards his soul, he enters into the sphere of intelligences, he feels himself attracted by the ideas of the beautiful, of the true, of the just; he participates in the condition of the spiritual beings, aspires to the immense, to the infinite; and is susceptible of an ever-increasing perfectibility, finding within himself the power of abhorring moral evil, viz., vice, and of cleaving to moral good, viz., virtue.

XV. Man has, therefore, within himself a germ of discord between the two principles of which he is constituted, a contrast between the exigencies of the body and those of the soul between the appetites of the senses and the dictates of reason; and as this latter alone is competent to form a judgment on what he ought or ought not to do, it follows that reason alone should be consulted and obeyed in determining upon every action.

XVI. Now, by freely and spontaneously resolving to conform all the actions of his life to the dictates of reason, which commands him to be wise in his self-government, upright with others, and pious towards the supreme Author, man will have worthily corresponded to the end for which he was created he will have fulfilled his destination; for it is clearly the destination of man to make the best possible use of the sublime faculties with which his soul is endowed; and the best possible use he does make when he subordinates his inferior to his superior tendencies, the cravings of the body to those of the soul; in a word, when he obeys the dictates of reason.

XVII. When man obeys the dictates of reason, an internal voice in his heart tells him that he has done right; he feels satisfied with himself, and is penetrated with a sense of true joy. When, on the contrary, he consciously infringes the laws of reason, he is not only deprived of that internal approbation, but an inextinguishable voice rises reproachful within his heart; he is no longer satisfied with himself, but feels uneasiness and perturbation. That internal voice, which judges man’s actions, and generates happiness or sorrow, is what is called Conscience.

XVIII. But the human soul, when it concentrates itself within, has also the faculty of feeling the sense of its own individuality, and perceiving that the state in which it is is its own. By virtue of this sense, which we may call feeling, the soul is led always to desire its own welfare, its own happiness; thence springs love or hatred, inclination or aversion towards an object, as this object seems apt to occasion pleasure or pain. But man, sooner or later, discovers that a true and permanent pleasure cannot be obtained through any of the physical enjoyments on earth, which he may not always be able to procure, or, when procured, leave after them weariness and disgust. He, consequently, cannot place in them his true happiness; and his internal sense tells him that there are other enjoyments of a purely spiritual nature, which alone can satisfy the highest aspirations of his soul. The exercise of his moral duties which, through his freedom of action, lies always within his power, and by which alone he can tranquillise his conscience and fully delight in self-contentment is that which offers to his soul true and permanent enjoyment; that alone is worth desiring.