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.