LECTIO FOURTEEN

             § 795. Having studied the soul in its vegetative, sensitive and intellectual parts, the Philosopher now considers it as a subject of movement. Introducing the problem, he observes first of all that the old philosophers defined the life-principle of animals in terms of two capacities: the capacity to discern or know, which is the function of intellect and sense; and the capacity to move from place to place. It is the latter capacity that we are concerned with now. We want to understand the principle of movement in relation to the soul: whether, if it is a part of the soul, it is really spatially separate from the other parts, so that it is located in a special part of the body, as the Platonists supposed; or, on the contrary, separable only in thought; whether perhaps it is not a part at all, but the entire soul; and whether, granted that it is only a part, it is or is not distinct from the parts usually enumerated, and distinct from those already studied in this treatise.

             § 796. Next, at 'A difficulty etc.', he begins a controversial section, which itself leads him, at 'It seems that there are two', to certain conclusions. This section contains two parts: (1) an argument against a certain division of the powers of the soul; and (2) an argument, at 'But of local motion', concerning especially the motive-principle as a part of the soul. As regards (1) he first states a division of the powers of the soul made by some philosophers, and then, at 'For according to', disputes it.

             He begins then by saying that we are met at the outset of our enquiry by the problem of dividing the soul's powers. What should be the principle of this division, and how many powers are there? It has seemed to some that the number of these powers was infinite, i.e. quite indeterminable; and this would indeed be the truth if every act or movement in the soul had to be assigned to its own distinct part. Thus it would seem inadequate to divide the soul, as some do, into a rational part, an irascible part, and an appetitive (i.e. concupiscible) part; for these include only the motive powers of the soul.

             § 797. And if others make the dividing line fall between the powers that share in reason and those that do not, this division, though comprehensive enough in a sense, is not exactly relevant to the parts of the soul as such, but only to the parts of the rational soul; and so Aristotle uses it in the Ethics.

             § 798. Next, at 'For according to the differences', he brings several objections against these divisions. (1) Granted that the differences just mentioned between the various parts of the soul are truly differences, they are not the only ones; the soul has other parts, already mentioned in this Treatise, which differ even more from one another. For instance, in all plants and animals (and thus in all living things) exists the vegetative part; and in all animals the sensitive part; and these two obviously differ from each other, and also from the rational, irascible and concupiscible parts, more than these last two parts from each other. Yet neither is included in the divisions given above.

             § 799. Not, it is clear, in the first division: for neither vegetability nor sensitivity can be called either rational, irascible or concupiscible. Again, passing to the second division, Aristotle shows that neither vegetability nor sensitivity are envisaged thereby. It is difficult, he says, to identify either with what shares or does not share in reason.

             § 800. That neither is rational in nature is obvious; but we can also show that neither is irrational. For the irrational means what is either anti-rational or lacking a rationality that it ought to possess; and neither of the aforesaid parts is such. Whereas if one were simply to call them non-rational they would not constitute, properly speaking, a classification of the soul's powers. Clearly, then, the aforesaid divisions are inadequate.

             § 801. (2) Then, at 'Further, there is', he observes that it is very hard to decide whether imagination, which can certainly be distinguished in thought from the rest of the soul, is or is not really the same thing as any one of the powers already mentioned; especially if we were to follow those who say that the parts of the soul are really separate beings.

             § 802. (3) Then again, at 'Furthermore, there is', he remarks that the appetitive capacity seems distinct, both in thought and as a real potency, from other parts of the soul. Now, assuming that the soul was so divided into a rational and an irrational part that each was a thing distinct from the other, one would have to 'split up', i.e. to divide the appetitive capacity in the same way--a very questionable procedure; and yet this capacity is certainly in part rational or volitional, and in part irrational (the irascible and concupiscible parts). Similarly, if we add the irascible part as a distinct thing to the rational and irrational parts of the soul, we should have to posit a different appetitive force in each: in one a volitional force, in another an irascible force, and in the third a concupiscible force; making three distinct things of this kind.

             § 803. But the question now arises why the sensitive part of the soul has two appetitive capacities, the irascible and the concupiscible, whereas there is only one rational appetitive force, the will. I answer that potencies differ according to the objective terms of their acts; and the objective term of appetite is the good as apprehended.

             § 804. Now the intellect and the senses apprehend the good differently: the intellect apprehends it under a general idea of goodness; but the senses in this or that particular determination. And this is why there is only one kind of appetite following intellectual apprehension, whereas the desire arising from sensuous apprehension divides according to diverse kinds of apprehended good. For some things seem good to the senses simply as affording pleasure; and this kind of goodness is answered by the concupiscible appetite. But other things seem good and desirable as terminating in pleasure in so far as by means of them one is enabled freely to enjoy pleasant things; and to this good corresponds the irascible appetite; which fights, as it were, on behalf of the concupiscible. Thus animals only get angry and fight for things that will afford them pleasure, that is to say, when they are hunting or mating, as it says in Book VI of the Historia Animalium.

             § 805. Therefore every movement of the irascible appetite starts from and ends in a movement of the concupiscible appetite. Anger springs from a sadness and ceases in a pleasure; for the angry find their satisfaction in punishing. Hence some say that to overcome obstacles is the precise object of the irascible appetite.

             § 806. But it is quite unreasonable to say, as some do, that the specific function of this appetite is to avoid evils. For one and the same potency bears upon contraries--as sight upon both black and white; hence good and evil cannot by themselves differentiate the appetitive potency. Hence, just as loving some good pertains to the concupiscible appetite, so does hating an evil (as Aristotle says in Book IX of the Ethics); and similarly both the hope of good and the fear of evil pertain to the irascible appetite.

             § 807. Then, at 'But to come', he observes that what we are at present concerned to elucidate (the principle of local movement in animals) does not seem to be accounted for by the aforesaid divisions; and that this is a further point against the latter. Now clearly the movements of growth and decline, common to all living things, spring from some common generative and vegetative principle; whereas certain other mutations, such as breathing in and out, or sleeping and waking, are not at all easy to explain and require to be treated of separately later.

             § 808. Then, at 'But of local motion', he asks what is the principle of local movement in animals. And he shows first that it is not the vegetative principle; secondly, at 'Likewise', that it is not sensitivity; thirdly, at 'Nor is the reasoning faculty', that it is not the intellect; and fourthly, at 'But not even appetition', that it is not the appetitive power.

             That it is not the vegetative principle he proves by two arguments. The first is as follows. Local movement from place to place is always occasioned by something the animal imagines and desires; no animal moves (except under compulsion) unless it wants, or withdraws from, something. But since the vegetative principle is without imagination and desire, it cannot be the principle of this kind of local movement.

             § 809. The second argument at 'Further: plants', runs thus. If the vegetative part were this principle, all plants would move about in this way, and be equipped with the necessary organs for doing so: which they obviously do not and are not. Therefore . . .

             § 810. Next, at 'Likewise', he shows that sensitivity is not the principle we are seeking. For if it were, every animal would have the power to move from place to place. But many animals, though capable of sensation, are fixed in one place and motionless so long as they live.

             § 811. And to meet the objection that perhaps the reason why such animals are immobile is that they lack, not the principle, but the organs of movement, he adds that Nature is never purposeless: it never fails to provide what is necessary for a given animal, unless this animal is deformed or a monster; and such monsters are exceptions to the normal course of nature, being caused by some defect or other in the parental seed. Now these immobile animals are perfect in their own way, not deformed like monsters: they generate offspring in their own likeness and grow and decline quite normally. In them, therefore, Nature does not act without purpose or fail in what is necessary for life. If then they were endowed with a motive-principle they would also have organs of motion; otherwise this principle would be useless, being unequipped with the necessary instruments. Note that this reasoning implies that wherever a vital principle exists there also will be found a corresponding organic apparatus; and that the parts of a living body subserve the powers of its soul.

             § 812. Next, where he says 'Nor is the reasoning faculty', he shows that not even mind is the motive-principle we seek. His words, 'nor is the reasoning faculty . . . called intellect', indicate, by the way, that reason and intellect are not distinct parts of the soul. The intellect is called 'reason' in so far as it comes to intelligible truths by a process of enquiry.

             § 813. That intellect is not the principle of movement he first proves with regard to the speculative intellect. So far as the mind merely considers things which are simply objects of speculation, not things to be done (e.g. that a triangle has three angles equal to two right angles) it is obviously not concerned with action and makes no judgement as to what should be avoided or pursued. In this state therefore the mind initiates no movement; for all movement is a pursuit of, or withdrawal from, something, by way of appetition.

             § 814. Again, the mind sometimes considers something to be done, yet not in a practical or effective way, but only speculatively,--considering it universally, not in view of an action in the particular. So he says that so far as the 'speculative' mind considers 'something of this kind', i.e. as the intellect regards even a practical affair in a merely speculative way, it makes no decision as yet about decision or flight. Thus we can often think of terrible or desirable things without commanding ourselves to fear or desire them; even if, for example, our hearts are moved by fear. And if, he adds, it is a desirable thing that moves us, it does so through some other organ than the heart.

             § 815. (This he adds with Plato in mind, who located the parts of the soul in different parts of the body, the irascible part, whence fear arises, in the heart; and the concupiscible in some other organ such as the liver.) Clearly then a merely speculative consideration, even of something practical, does not of itself move to action. As such the speculative intellect is in no way a motive power.

             § 816. Next at 'Further, when', he shows that not even the practical intellect moves to action. For when a man, he says, comes to a decision, understanding that something should be avoided or pursued, he may nevertheless fail to follow this intellectual decision and follow his feelings instead,--as incontinent people do, who know what ought to be done but fail to carry it out. It would seem therefore that mere intellect does not suffice to move us. Similarly, doctors may know quite well how to recover health, yet not recover it, because they fail to put into practice their own prescriptions. Apparently then, to act according to knowledge involves something else besides even practical knowledge.

             § 817. Lastly, with 'But not even appetition', he shows that the appetitive part itself does not simply command our movements; for we may see continent people in a state of want and desire yet refusing to act according to their desires. And the converse is true of the incontinent, as he explains more clearly in the Ethics, Book VII. So it seems that neither is appetition the cause of movement.

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