1. The Interaction of the Soul and Body

There are three opinions and traditions, which are hypotheses, concerning the Interaction of the Soul and Body, or the operation of the one upon the other, and of the one together with the other: the first is called Physical Influx, the second Spiritual Influx, and the third Pre-established Harmony.

The first, which is called physical influx, arises from the appearances of the senses, and the fallacies thence derived. For it appears as if the objects of sight, which affect the eyes, flow into the thought and produce it; in like manner speech, which affects the ears, appears to flow into the mind, and to produce ideas there; and it is similar with respect to the senses of smell, taste, and touch. Since the organs of these senses first receive the impressions that flow into them from the world, and the mind appears to think, and also to will, according as these organs are affected, therefore, the ancient philosophers and Schoolmen believed that influx was derived from them into the soul, and hence adopted the hypothesis of Physical or Natural Influx.

[2] The second hypothesis, which is called spiritual, and by some occasional influx, originates in order and its laws. For the soul is a spiritual substance, and therefore purer, prior, and interior; but the body is material, and therefore grosser, posterior, and exterior; and it is according to order that the purer should flow into the grosser, the prior into the posterior, and the interior into the exterior, thus what is spiritual into what is material, and not the contrary. Consequently, it is according to order for the thinking mind to flow into the sight according to the state induced on the eyes by the objects before them, which state that mind also disposes at its pleasure; and likewise for the perceptive mind to flow into the hearing, according to the state induced upon the ears by speech.

[3] The third hypothesis, which is called pre-established harmony, arises from the appearances and fallacies of the reasoning faculty; since the mind, in the very act of operating, acts together with and at the same time as the body. Still, every operation is first successive and afterwards simultaneous, and successive operation is Influx, and simultaneous operation is Harmony; as, for instance, when the mind thinks and afterwards speaks, or when it wills and afterwards acts: hence it is a fallacy of the reasoning faculty to establish that which is simultaneous, and to exclude that which is successive.

No fourth opinion concerning the Interaction of the Soul and the Body can be framed in addition to these three; for either the soul must operate upon the body, or the body upon the soul, or both uninterruptedly at the same time.

15. XIII. It is altogether otherwise with beasts.

Those who judge from the mere appearance presented to the senses of the body conclude that beasts have will and understanding just in the same manner as men, and hence that the only distinction consists in a man's being able to speak, and thus to utter the things which he thinks and desires, while beasts can only express them by sounds. Beasts, however, have not will and understanding, but only a resemblance of each, which the learned call an analogue.

[2] A man is a man, because his understanding can be raised above the desires of his will, and thus, from above can know and see them, and also govern them; but a beast is a beast, because its desires impel it to do whatever it does. A man is thus a man from the fact that his will is under obedience to his understanding; but a beast is a beast from the circumstance that its understanding is under obedience to its will. From these considerations this conclusion follows: that a man's understanding is alive, and thence a true understanding, because it receives the light flowing in from heaven, and takes possession of it and regards it as its own, and thinks from it analytically with all variety, altogether as if from itself; and that a man's will is alive, and is thence truly will, because it receives the inflowing love of heaven, and acts from it as if from itself; but that the contrary is the case with beasts.

[3] Therefore those who think from the lusts of the will are compared to beasts, and likewise, in the spiritual world, appear at a distance as beasts; they also act like beasts, with only this difference, that they are able to act otherwise if they wish. Those, on the other hand, who restrain the lusts of their will by means of the understanding, and thence act rationally and wisely, appear in the spiritual world as men, and are angels of heaven.

[4] In a word, the will and the understanding in beasts always work together; and because the will in itself is blind, being a thing of heat and not of light, it makes the understanding blind also. Hence a beast does not know and understand its own actions; yet it acts, notwithstanding, for it acts by an influx from the spiritual world, and such action is instinct.

[5] It is supposed that a beast thinks from the understanding what to do; but it does not in the least: it is induced to act solely from the natural love which is in it from creation, with the assistance of the senses of its body. The reason that a man thinks and speaks is simply that his understanding is capable of being separated from his will, and of being raised even into the light of heaven; for the understanding thinks, and the thought speaks.

[6] The reason why beasts act according to the laws of order inscribed on their nature, and some of them (differently from many men) in, as it were, a moral and rational manner, is that their understanding is in blind obedience to the desires of their will, and thence they have not been able to pervert those desires by depraved reasonings, as men do. It is to be observed that by the will and understanding of beasts in the foregoing statements we mean a certain resemblance and analogue of those faculties. The analogues are called by the names of those faculties on account of the appearance.

[7] The life of a beast may be compared with a sleep-walker, who walks and acts by virtue of the will while the understanding sleeps; and also with a blind man, who passes through the streets with a dog leading him; as likewise with an idiot, who from custom and the habit thence acquired does his work according to rules. It may be similarly compared with a person devoid of memory, and thence deprived of understanding, who still knows or learns how to clothe himself, to eat the food which he prefers, to love the sex, to walk the streets from house to house, and to do such things as soothe the senses and indulge the flesh, by the allurements and pleasures of which things he is drawn along, though he does not think, and therefore cannot speak.

[8] From these considerations it is evident how much those are mistaken who believe that beasts enjoy rationality, and that they are only distinguished from men by their outward form, and by their inability to express by speech the rational things which they conceal within; from which fallacies many even conclude that if a man lives after death, a beast will live also; and, conversely, that if a beast does not live after death, neither will a man; besides other fancies arising from ignorance in regard to the will and understanding, and also concerning degrees, by means of which, as by a flight of stairs, the mind of a man mounts up to heaven.