Those two faculties, the appetite and the mind, appear to be the motor principles in animals—the mind, if the imagination might be set down as being a kind of thought; for many against knowledge follow their imaginings, and other animals are moved neither by thought nor calculation, but by imagination. Thus, those two faculties, mind and appetite, are locomotive powers; but, then, it is mind in the sense of a calculating and a practical faculty, and which differs from the speculative mind by the object to which it tends. Now, every appetite tends to some object, for the appetite, which is the beginning of the practical mind, has ever some object in view, and that object is the beginning of the action. So that these two, appetite and practical thought, may reasonably be regarded as motor powers—for the object longed for impels to move, and then, through it, the practical intelligence impels, because its origin is the object longed for; and when imagination may incite to move, it never does set in motion without appetite. Thus, it is the object longed for alone which produces motion; for if there were two motives, mind and appetite, they would produce motion according to some common formula. But as the case is, the mind does not appear to produce motion without appetite, for volition is appetite; and even when a creature may move by calculation, it still moves by volition; the appetite, on the contrary, impels to move against calculation, for desire is a kind of appetite.
The mind then is always right; but appetite as well as imagination may be right and may be wrong. It is, therefore, the object desired which always excites to move, but then that object is a good or an apparent good; not however, a good in every sense, but a practical good, and a practical good admits of being otherwise than good.
It is manifest then, that it is that faculty of Vital Principle, the so-called appetite which excites to move. But when Vital Principle is divided into parts, and parts are distinguished by their faculties, very many are made apparent, as the nutritive, the sentient, the cogitative, the deliberative, and the appetitive, and these differ from one another more than do the desiring and the passionate.
The appetites admit of being opposed to one another, and this occurs when reason may be opposed to desire, but the opposition can be manifested only in beings with a sense of time; for the mind commands to resist on account of the future, while desire urges to immediate compliance, as that which is good appears, as the future is unseen, to be absolutely good and absolutely grateful. Thus, the appetitive faculty, in so far as appetitive, may, in a specific sense, be the motor, but it is the object desired by appetite which is the first to set in motion ; for without having been itself moved, it incites to move from having been thought upon or imagined; and there are several such motors. There are three terms here : the motor; then that by which it moves; and thirdly, that which is moved. But the motor is in the two-fold sense of unmoved, and both motor, and moved—the unmoved is the practical good ; the motor and moved is the appetitive stimulus or appetition (for that which is moved moves only in so far as it desires, and appetite is a motion or an act of some kind) ; and the moved is the animal. As the organism by which appetite effects motion is obviously corporeal, its nature must be studied together with those functions which are common to the body and the Vital Principle. But to speak summarily, the organism whereby motion is effected, is as a hinge in which coexist the beginning and the end of motion—for herein are the convex and the concave, of which that is the beginning, and this the end of motion; and therefore the one is at rest while the other is in motion, as although, rationally considered, the two pieces are distinct, yet, substantively, they are inseperable.
In fine, then, as has been said, an animal is endowed with self-motion to the extent of its appetition; but it cannot be susceptible of appetite without imagination, and all imagination is either rational or sentient, and of this latter kind other animals partake also.
Notes
Note 1, p. 178. Thus it is the object longed for alone, &c.] Food, that is, being necessary both for stilling the appetite and preserving the body, is the first motor; for, were there, as the text says, two motors, then, as the practical mind never impels to move without appetite, appetite could not impel to move without the mind, which is not the case. This is the argument; but it is less distinct than might be wished for owing to the nature of the practical mind not having been defined, and to insufficient knowledge concerning both muscular agency and the brain and nervous system.
Note 2, p. 178. The mind then is always right, &c.] The intellect, that is, when neither moved by appetite nor perverted by imagination, (for both may be wrong) is, when freed from those influences, always right; but food incites to move because it is either good or appears to be a good, in the sense, not of a moral but, of a practical good, and, as such, it may, by abuse, be the opposite of good.
Note 3, p. 179. The appetites admit of being opposed, &c.] "Appetite and reason are not always in accordance," Aristotle[1] observes, and as, when any one desire is subdued another may arise and strive for the mastery, so appetite may well be opposed to appetite. But resistance to desire can be manifested only in such beings as have a sense of time, have, that is, powers of abstraction, by which, withdrawing themselves from what is present, and foreseeing consequences in the future, they are enabled to resist the immediate compliance which desire or passion is urging upon them. For "the[2] portion of time now present, is a portion of that which is future and indivisible."
Note 4, p. 179. For without having been itself moved, &c.] Owing to the wording there is obscurity about this passage, but yet it may be elucidated—the object desired, food, that is, although at rest, may, acting upon the appetitive sense, incite to move, and so be regarded as a motor; and there are, of course, as many such motors as there are kinds of food. These then are the three terms—first, the motor or food; then the muscular agency by which locomotion is effected; and lastly, that which is moved, or the animal.
Note 5, p. 180. But to speak summarily, &c.] The passage has, in this version, been rendered with a bias that the analogy was drawn from the structure of the knee-joint, which, in all times, has been likened to a hinge, and hence termed " ginglymoid;" and conchologists, following Aristotle[3], have so termed the hinge of the bivalves. The Latin is, "nunc ut in summa dicamus, id quod movet ut instrumentum, ibi est collocandum ubi idem principii rationem finisve subit ut in cardine fit—hinc enim convexum et concavum est; quorum alterum finis, alterum principium est; quapropter alienum quiescit alterum movetur." The closing paragraph seems to confirm what has been assumed, that sentient imagination is analogous to "animal instinct."