Summa Theologica Part I (Prima Pars) Part 130

According to this opinion, then, on the part of the phantasms, intellectual knowledge is caused by the senses. But since the phantasms cannot of themselves affect the pa.s.sive intellect, and require to be made actually intelligible by the active intellect, it cannot be said that sensible knowledge is the total and perfect cause of intellectual knowledge, but rather that it is in a way the material cause.

Reply Obj. 1: Those words of Augustine mean that we must not expect the entire truth from the senses. For the light of the active intellect is needed, through which we achieve the unchangeable truth of changeable things, and discern things themselves from their likeness.

Reply Obj. 2: In this pa.s.sage Augustine speaks not of intellectual but of imaginary knowledge. And since, according to the opinion of Plato, the imagination has an operation which belongs to the soul only, Augustine, in order to show that corporeal images are impressed on the imagination, not by bodies but by the soul, uses the same argument as Aristotle does in proving that the active intellect must be separate, namely, because "the agent is more n.o.ble than the patient." And without doubt, according to the above opinion, in the imagination there must needs be not only a pa.s.sive but also an active power. But if we hold, according to the opinion of Aristotle, that the action of the imagination is an action of the "composite," there is no difficulty; because the sensible body is more n.o.ble than the organ of the animal, in so far as it is compared to it as a being in act to a being in potentiality; even as the object actually colored is compared to the pupil which is potentially colored. It may, however, be said, although the first impression of the imagination is through the agency of the sensible, since "fancy is movement produced in accordance with sensation" (De Anima iii, 3), that nevertheless there is in man an operation which by synthesis and a.n.a.lysis forms images of various things, even of things not perceived by the senses.

And Augustine's words may be taken in this sense.

Reply Obj. 3: Sensitive knowledge is not the entire cause of intellectual knowledge. And therefore it is not strange that intellectual knowledge should extend further than sensitive knowledge.

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SEVENTH ARTICLE [I, Q. 84, Art. 7]

Whether the Intellect Can Actually Understand Through the Intelligible Species of Which It Is Possessed, Without Turning to the Phantasms?

Objection 1: It would seem that the intellect can actually understand through the intelligible species of which it is possessed, without turning to the phantasms. For the intellect is made actual by the intelligible species by which it is informed. But if the intellect is in act, it understands. Therefore the intelligible species suffices for the intellect to understand actually, without turning to the phantasms.

Obj. 2: Further, the imagination is more dependent on the senses than the intellect on the imagination. But the imagination can actually imagine in the absence of the sensible. Therefore much more can the intellect understand without turning to the phantasms.

Obj. 3: There are no phantasms of incorporeal things: for the imagination does not transcend time and s.p.a.ce. If, therefore, our intellect cannot understand anything actually without turning to the phantasms, it follows that it cannot understand anything incorporeal.

Which is clearly false: for we understand truth, and G.o.d, and the angels.

_On the contrary,_ The Philosopher says (De Anima iii, 7) that "the soul understands nothing without a phantasm."

_I answer that,_ In the present state of life in which the soul is united to a pa.s.sible body, it is impossible for our intellect to understand anything actually, except by turning to the phantasms.

First of all because the intellect, being a power that does not make use of a corporeal organ, would in no way be hindered in its act through the lesion of a corporeal organ, if for its act there were not required the act of some power that does make use of a corporeal organ. Now sense, imagination and the other powers belonging to the sensitive part, make use of a corporeal organ. Wherefore it is clear that for the intellect to understand actually, not only when it acquires fresh knowledge, but also when it applies knowledge already acquired, there is need for the act of the imagination and of the other powers. For when the act of the imagination is hindered by a lesion of the corporeal organ, for instance in a case of frenzy; or when the act of the memory is hindered, as in the case of lethargy, we see that a man is hindered from actually understanding things of which he had a previous knowledge. Secondly, anyone can experience this of himself, that when he tries to understand something, he forms certain phantasms to serve him by way of examples, in which as it were he examines what he is desirous of understanding. For this reason it is that when we wish to help someone to understand something, we lay examples before him, from which he forms phantasms for the purpose of understanding.

Now the reason of this is that the power of knowledge is proportioned to the thing known. Wherefore the proper object of the angelic intellect, which is entirely separate from a body, is an intelligible substance separate from a body. Whereas the proper object of the human intellect, which is united to a body, is a quiddity or nature existing in corporeal matter; and through such natures of visible things it rises to a certain knowledge of things invisible. Now it belongs to such a nature to exist in an individual, and this cannot be apart from corporeal matter: for instance, it belongs to the nature of a stone to be in an individual stone, and to the nature of a horse to be in an individual horse, and so forth. Wherefore the nature of a stone or any material thing cannot be known completely and truly, except in as much as it is known as existing in the individual. Now we apprehend the individual through the senses and the imagination. And, therefore, for the intellect to understand actually its proper object, it must of necessity turn to the phantasms in order to perceive the universal nature existing in the individual. But if the proper object of our intellect were a separate form; or if, as the Platonists say, the natures of sensible things subsisted apart from the individual; there would be no need for the intellect to turn to the phantasms whenever it understands.

Reply Obj. 1: The species preserved in the pa.s.sive intellect exist there habitually when it does not understand them actually, as we have said above (Q. 79, A. 6). Wherefore for us to understand actually, the fact that the species are preserved does not suffice; we need further to make use of them in a manner befitting the things of which they are the species, which things are natures existing in individuals.

Reply Obj. 2: Even the phantasm is the likeness of an individual thing; wherefore the imagination does not need any further likeness of the individual, whereas the intellect does.

Reply Obj. 3: Incorporeal things, of which there are no phantasms, are known to us by comparison with sensible bodies of which there are phantasms. Thus we understand truth by considering a thing of which we possess the truth; and G.o.d, as Dionysius says (Div. Nom. i), we know as cause, by way of excess and by way of remotion. Other incorporeal substances we know, in the present state of life, only by way of remotion or by some comparison to corporeal things. And, therefore, when we understand something about these things, we need to turn to phantasms of bodies, although there are no phantasms of the things themselves.

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EIGHTH ARTICLE [I, Q. 84, Art. 8]

Whether the Judgment of the Intellect Is Hindered Through Suspension of the Sensitive Powers?

Objection 1: It would seem that the judgment of the intellect is not hindered by suspension of the sensitive powers. For the superior does not depend on the inferior. But the judgment of the intellect is higher than the senses. Therefore the judgment of the intellect is not hindered through suspension of the senses.

Obj. 2: Further, to syllogize is an act of the intellect. But during sleep the senses are suspended, as is said in _De Somn. et Vigil._ i and yet it sometimes happens to us to syllogize while asleep.

Therefore the judgment of the intellect is not hindered through suspension of the senses.

_On the contrary,_ What a man does while asleep, against the moral law, is not imputed to him as a sin; as Augustine says (Gen. ad lit.

xii, 15). But this would not be the case if man, while asleep, had free use of his reason and intellect. Therefore the judgment of the intellect is hindered by suspension of the senses.

_I answer that,_ As we have said above (A. 7), our intellect's proper and proportionate object is the nature of a sensible thing. Now a perfect judgment concerning anything cannot be formed, unless all that pertains to that thing's nature be known; especially if that be ignored which is the term and end of judgment. Now the Philosopher says (De Coel. iii), that "as the end of a practical science is action, so the end of natural science is that which is perceived princ.i.p.ally through the senses"; for the smith does not seek knowledge of a knife except for the purpose of action, in order that he may produce a certain individual knife; and in like manner the natural philosopher does not seek to know the nature of a stone and of a horse, save for the purpose of knowing the essential properties of those things which he perceives with his senses. Now it is clear that a smith cannot judge perfectly of a knife unless he knows the action of the knife: and in like manner the natural philosopher cannot judge perfectly of natural things, unless he knows sensible things. But in the present state of life whatever we understand, we know by comparison to natural sensible things. Consequently it is not possible for our intellect to form a perfect judgment, while the senses are suspended, through which sensible things are known to us.

Reply Obj. 1: Although the intellect is superior to the senses, nevertheless in a manner it receives from the senses, and its first and princ.i.p.al objects are founded in sensible things. And therefore suspension of the senses necessarily involves a hindrance to the judgment of the intellect.

Reply Obj. 2: The senses are suspended in the sleeper through certain evaporations and the escape of certain exhalations, as we read in _De Somn. et Vigil._ iii. And, therefore, according to the amount of such evaporation, the senses are more or less suspended. For when the amount is considerable, not only are the senses suspended, but also the imagination, so that there are no phantasms; thus does it happen, especially when a man falls asleep after eating and drinking copiously. If, however, the evaporation be somewhat less, phantasms appear, but distorted and without sequence; thus it happens in a case of fever. And if the evaporation be still more attenuated, the phantasms will have a certain sequence: thus especially does it happen towards the end of sleep in sober men and those who are gifted with a strong imagination. If the evaporation be very slight, not only does the imagination retain its freedom, but also the common sense is partly freed; so that sometimes while asleep a man may judge that what he sees is a dream, discerning, as it were, between things, and their images. Nevertheless, the common sense remains partly suspended; and therefore, although it discriminates some images from the reality, yet is it always deceived in some particular. Therefore, while man is asleep, according as sense and imagination are free, so is the judgment of his intellect unfettered, though not entirely.

Consequently, if a man syllogizes while asleep, when he wakes up he invariably recognizes a flaw in some respect.

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QUESTION 85

OF THE MODE AND ORDER OF UNDERSTANDING (In Eight Articles)

We come now to consider the mode and order of understanding. Under this head there are eight points of inquiry:

(1) Whether our intellect understands by abstracting the species from the phantasms?

(2) Whether the intelligible species abstracted from the phantasms are what our intellect understands, or that whereby it understands?

(3) Whether our intellect naturally first understands the more universal?

(4) Whether our intellect can know many things at the same time?

(5) Whether our intellect understands by the process of composition and division?

(6) Whether the intellect can err?

(7) Whether one intellect can understand better than another?

(8) Whether our intellect understands the indivisible before the divisible?

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FIRST ARTICLE [I, Q. 85, Art. 1]

Whether Our Intellect Understands Corporeal and Material Things by Abstraction from Phantasms?

Objection 1: It would seem that our intellect does not understand corporeal and material things by abstraction from the phantasms. For the intellect is false if it understands an object otherwise than as it really is. Now the forms of material things do not exist as abstracted from the particular things represented by the phantasms.

Therefore, if we understand material things by abstraction of the species from the phantasm, there will be error in the intellect.

Obj. 2: Further, material things are those natural things which include matter in their definition. But nothing can be understood apart from that which enters into its definition. Therefore material things cannot be understood apart from matter. Now matter is the principle of individualization. Therefore material things cannot be understood by abstraction of the universal from the particular, which is the process whereby the intelligible species is abstracted from the phantasm.

Obj. 3: Further, the Philosopher says (De Anima iii, 7) that the phantasm is to the intellectual soul what color is to the sight. But seeing is not caused by abstraction of species from color, but by color impressing itself on the sight. Therefore neither does the act of understanding take place by abstraction of something from the phantasm, but by the phantasm impressing itself on the intellect.

Obj. 4: Further, the Philosopher says (De Anima iii, 5) there are two things in the intellectual soul--the pa.s.sive intellect and the active intellect. But it does not belong to the pa.s.sive intellect to abstract the intelligible species from the phantasm, but to receive them when abstracted. Neither does it seem to be the function of the active intellect, which is related to the phantasm, as light is to color; since light does not abstract anything from color, but rather streams on to it. Therefore in no way do we understand by abstraction from phantasms.

Obj. 5: Further, the Philosopher (De Anima iii, 7) says that "the intellect understands the species in the phantasm"; and not, therefore, by abstraction.

_On the contrary,_ The Philosopher says (De Anima iii, 4) that "things are intelligible in proportion as they are separate from matter."

Therefore material things must needs be understood according as they are abstracted from matter and from material images, namely, phantasms.

_I answer that,_ As stated above (Q. 84, A. 7), the object of knowledge is proportionate to the power of knowledge. Now there are three grades of the cognitive powers. For one cognitive power, namely, the sense, is the act of a corporeal organ. And therefore the object of every sensitive power is a form as existing in corporeal matter. And since such matter is the principle of individuality, therefore every power of the sensitive part can only have knowledge of the individual. There is another grade of cognitive power which is neither the act of a corporeal organ, nor in any way connected with corporeal matter; such is the angelic intellect, the object of whose cognitive power is therefore a form existing apart from matter: for though angels know material things, yet they do not know them save in something immaterial, namely, either in themselves or in G.o.d. But the human intellect holds a middle place: for it is not the act of an organ; yet it is a power of the soul which is the form of the body, as is clear from what we have said above (Q. 76, A. 1). And therefore it is proper to it to know a form existing individually in corporeal matter, but not as existing in this individual matter. But to know what is in individual matter, not as existing in such matter, is to abstract the form from individual matter which is represented by the phantasms. Therefore we must needs say that our intellect understands material things by abstracting from the phantasms; and through material things thus considered we acquire some knowledge of immaterial things, just as, on the contrary, angels know material things through the immaterial.

But Plato, considering only the immateriality of the human intellect, and not its being in a way united to the body, held that the objects of the intellect are separate ideas; and that we understand not by abstraction, but by partic.i.p.ating things abstract, as stated above (Q. 84, A. 1).