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Chapter III



"The human soul," says Alfarabi, "is a unity in difference. This means that the soul is one, and that its unity is the basis for certain differences or powers. The powers of the soul are multiple but can be reduced to three kinds: vegetative, sensitive and intellective." 89 Hence the following schema:

The Soul is: Vegetative, Sensitive, Intellective.

1. The Vegetative has three Powers: Nutritive, Augmentative, Generative.

2. The Sensitive has two Powers:

(a) Powers of Knowledge: External sensible (five external senses), Internal sensible (Imagination, Memory, Estimative power).

(b) Powers of Action: Sensitive (Concupiscible and Irascible), Locomotive.

3. The Intellective has two Powers:

(a) Powers of Knowledge: Perceptive (knowledge of the individual), Abstractive (knowledge of the universal) is obtained through the four Intellects: Passive Intellect, Active Intellect, Actual Intellect, Acquired Intellect.

(b) Power of Action: Intellective (the will)

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In the exposition of the theory of knowledge we shall compare the theory of Alfarabi with that of St. Thomas for the purpose of helping the reader discover at a glance the similarity and the difference between them.


Every idea comes from sense-experience according to the adage: "There is nothing in the intellect that has not first been in the senses." The mind is like a smooth tablet on which nothing is written. It is the senses that do all the writing on it. The senses are five: sight, hearing, smell, taste and touch. Each of these has a proper sensible thing for its object. In every sensation the sense receives the form or species of sensible things without the matter, just as wax receives the form of a seal without any of the matter of it. 90


Now, sense is a passive power, and is naturally changed by the exterior sensible. Wherefore the exterior cause of such change is what is directly perceived by the sense, and according to the diversity of that exterior cause are the sensitive powers diversified. Now, change is of two kinds, one natural and the other spiritual. Natural change takes place by the form of the changer being received, according to its natural existence, into the thing changed, as heat is received into the thing heated. Whereas spiritual change takes place by the form of the changer being received, according to a spiritual mode of existence, into the thing changed, as the form of color is received into the pupil which does not thereby become colored. Now, for the operation of the senses, a spiritual change is required, whereby an intention of the sensible form is effected in sensible organ. 91


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If Alfarabi had worked out more in detail the theory of sense-knowledge, he probably would have brought out not only the physical factor, but also the psychical. For, he seems to take for granted the following factors which bring about sensation proper. First, without the organs of the several senses, there can be no sensation. We cannot see without eyes, nor hear without ears. A sense organ is a potentia passiva, the actuation of which is due to a stimulus, and ultimately to an object. Second, when the object acts upon the sense-organ, it must produce therein a modification which is like to itself, and generally called sensible species. In receiving the sensible species, the sense passes from potentia passiva to act. Hence, when sensible species are produced in a sentient organism, they must produce a corresponding reaction which we call sensation


The sensations we have once experienced are not utterly dead. They can reappear in the form of images. The power by which we revive a past sensible experience without the aid of any physical stimulus is called imagination (el-motakhayilah).

The power by which we combine and divide images is called the cogitative (el-mofakarah). If we were limited merely to the experience of our actual sensations, we would have only the present, and with it there would be no intellectual life at all. But fortunately we are endowed with the power of calling back a former experience, and this is called memory (el-hafizah- el-zakirah).


For the retention and preservation of these forms (sensible forms), the phantasy or imagination is appointed; which are the same, for phantasy or imagination is as it were a storehouse of forms received through the senses. Furthermore, for the apprehension of intentions which are not received through the senses, the estimative power is appointed: and for the preservation thereof, the memorative power, which is a storehouse of such like intentions 92


Finally, among the internal senses Alfarabi mentions instinct or el-uahm (the estimative power of the Scholastics), by which animals seek what is useful to them and avoid what is harmful. "It is by this faculty," he says, "that the sheep knows that the

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wolf is his enemy and that the little lambs need its care and attention." 93


If while hard at work writing, I smell something sweet but cannot tell where the sweet odor is coming from, I am said to have a sensation of smell. If I refer that "something sweet" to a rose on the table, then I have a percept of the smell of the rose. From this it follows that sensation is not knowledge (sentire est nondum scire) .

Man's first knowledge, according to Alfarabi, is a percept. A percept is a knowledge of the individual, free from abstraction; it is individuality without universality. It comes after sensation, but prior to a concept (knowledge of the universal). Literally he says: "There is one part of the soul in which occurs the first knowledge, a knowledge free from abstraction, and which apprehends the principles of science immediately and without reflection." 94

That a percept (knowledge of the individual) comes first, is proved by the fact that our mind must have the individual be-fore abstracting from it the universal. Hence, there is nothing in the intellect that has not been first in sense-perception.

But a percept is simply incomplete knowledge. To know the individual completely we must see it and understand it in relation to other individuals, which is like saying that we must conceive it and think of it.

For Alfarabi, what is commonly called thought or concept seems to represent something like the concrete universal, something like the universal existing in the particular concrete thing.

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[paragraph continues] This is easily inferred from his definition of the universal as "Unum de multis et in multis." By the word "Unum" he means that the universality, that common something, is abstracted from the concrete thing (percept); and by the words "de multis et in multis" he means that the universality is to be applied to concrete cases and is contained within them.

That Alfarabi holds universality in concreteness as peculiar features of the concept is seen from the fact that he does not admit in its absolute sense the aphorism "singulare sentitur, universale intelligitur." He rather believes that, while by its matter the particular concrete thing is the object of sense-perception, yet by its form or essence, it is in the intellect, too. On the other hand, though the universal, as such, is in the intellect, yet it is also in sense-perception insofar as it is immanent in the individual. 95


All our intellectual powers are grouped under our common name "intellect," by which we think, judge and reason. Alfarabi points out the various meanings of the term "intellect" as used in common speech and in philosophy proper. In everyday language "an intelligent man," he says, "means a man of reliable judgment, who knows what he has to do as right and what he has to avoid as wrong, and thus is distinguished from a crafty man who employs his mind in devising evil expedients." 96 He continues:

Theologians use the term "intellect" to denote the faculty which tests the validity of statements, either approving them as true or rejecting them as false. Hence, by "intellect" they mean the faculty which perceives the truths of common evidence. 97

In Analytics Aristotle uses the term "intellect" to denote

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the faculty by which man attains to the certain knowledge of axioms and general abstract truths without the need of proof. This faculty is that part of the soul in which occurs the first knowledge (sense percept), and which is thereby able to lay hold of the premises of speculative science. 98

In the book of Ethics Aristotle mentions an intellect of moral truths, and this is, for Alfarabi, that part of the soul in which moral experience, as we call it, takes place and by which we try to distinguish the acts to be done from those to be avoided. 99

Finally comes the intellect spoken of in the Anima, and is the intellect proper. This is of two kinds: the speculative intellect is an apprehensive power relating to what is above itself, while the practical intellect is a motive power referring to what is below itself, namely, to the sensitive world that it must govern. The speculative intellect, as treated by Alfarabi, consists of four faculties or parts of the soul: the passive and active intellects, the acquired intellect and the actual intellect.


The passive intellect or aql hayulani is in potentiality to things intelligible. It passes from potentiality to act when it separates mentally the essence from its individuating notes. This essence, abstracted from the individuals, becomes actually the intelligible form or species which is one and the same as the intellect in act.


The human intellect is in potentiality with regard to things intelligible, and is at first like a clean tablet on which nothing is written. This is made clear from the fact that at first we are only in potentiality to understand and afterwards we are made to understand actually. And so it is evident that with us to understand is in a way to be passive, and consequently the intellect is a passive power. 100



When forms existing in matter outside the soul become actually intelligible, their existence as

Nothing is reduced from potentiality to act except by something in act; as the senses are


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actually intelligible is not the same as forms existing in matter. For forms existing in matter (individualized concretely) are associated with the various categories of time and place, quantity and quality, but they are stripped of these individuating conditions the moment they become actually intelligible. 101

The active intellect, or aql faal of which Aristotle speaks in the Anima III, is causes the passive intellect to pass from potentiality to act, and makes the intelligible in potentiality intelligible in act.

The active intellect is related to the passive as the sun is to the eye. The eye is in potentiality to see while it is dark, but it sees actually as soon as light shines. The same is to be said of both the passive and active intellect.

The active intellect shines a kind of light upon the passive, by which the passive becomes actual, (aql bilfil) and the intelligible in potentiality becomes intelligible in act. Furthermore, the active intellect is a separate substance, which, by lighting up the phantasms, makes them to be actually intelligible. 104

made actual by what is actually sensible. We must therefore assign on the part of the intellect, some power, to make things actually intelligible, by the abstraction of the species from material conditions. And such is the necessity for an active intellect. 102

The intellectual soul is indeed actually immaterial, but it is in potentiality to determinate species. On the contrary, phantasms are actual images of certain species, but are immaterial in potentiality. Wherefore nothing prevents one and the same soul, inasmuch as it is actually immaterial, having one power by which it makes things actually immaterial, by abstraction from the conditions of individual matter: which power is called the active intellect; and another power, receptive of such species, which is called the passive intellect by reason of its being in potentiality to such species. 103




The acquired intellect or aql mustafad is simply the actual intellect developed under the inspiration of the active intellect. Albertus Magnus calls it "Intellectus adeptus" 106


Not only does the active intellect throw light on the phantasm; it does more. By its own power it abstracts the intelligible species from the phantasm. It throws light on the phantasm,


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because, just as the sensitive part acquires a greater power by its conjunction with the intellectual part, so by the power of the active intellect the phantasms are made more fit for the abstraction therefrom of intelligible intentions. Furthermore, the active intellect abstracts the intelligible species from the phantasm, forasmuch as by the power of the active intellect we are able to disregard the conditions of individuality, and to take into our consideration the specific nature, the image of which informs the passive intellect. 105



Alfarabi's theory may be summed up as follows: the intellect, in its primitive state, is a power of the soul. Since it has only a potential existence, he calls it "aql hayulani", the material intellect. For, like matter, it has the capacity for taking on a new form. In fact, the material or passive intellect passes from potentiality to actuality when it abstracts the essence from the individuals. But what is the force that causes the passive intellect to pass from potentiality to act? It is, according to Alfarabi, the active intellect, a separate 'substance emanating from God which is able to awaken the latent power in man and arouse it to activity.

St. Thomas' theory boils down to this: to abstract the essence and to perceive it are two acts specifically distinct; therefore they demand two distinct powers. Hence the soul requires one power which renders the essences of sensible things actually intelligible by stripping them of their material conditions in which they exist: which power is called the active intellect; and another power by which it comprehends the intelligible: this is called the passive intellect because of its being in potentiality to all intelligibles.


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"By powers of action," says Alfarabi, "are meant those powers which have action or movement for their object, and they are all grouped under the name of 'appetite.'" A general law rules our appetitive powers: "Nil volitum quin fuerit praecognitum." Appetite follows knowledge. For, appetite can never operate unless something is known and presented to it. Appetite may be moved either by the sense or by the intellect. If the appetite is moved by the sense, it becomes sensitive appetite. This is simply a tendency to good perceived by the senses.

Now, the sensitive appetite is divided into two powers, the concupiscible appetite and the irascible appetite. Concupiscible appetite (shahuaniat) is a power by which the animal is led to seek what is useful to it, and to shun what is harmful. Irascible appetite (Gadibat) is a power by which the animal is aroused to acquire a good that is difficult to attain, and to remove any evil that would prevent its attainment. By his concupiscible appetite a dog seeks proper food and avoids what is injurious; by his irascible appetite he is angered and attacks the animal that tries to deprive him of his food.

The manifestations of the concupiscible appetite are called concupiscible passions, and those of the irascible appetite are called irascible passions.

Alfarabi characterizes the nature of the sensitive appetite by saying that

It is accompanied by a physical, bodily change. Thus, for instance, when one is aroused by a great desire to see something, he looks up and stares at the thing. The

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looking up and the staring represent the bodily change. 107


If the appetite is moved by the intellect, it becomes intellective appetite, or will, and through it man attains his perfection and happiness. Of this Alfarabi says:

The will is not to be confused with freedom (the power of choice). Freedom can choose only what is possible, while the will can choose also the impossible. The latter is well exemplified in a man who does not will to die. Therefore, the will is more general than freedom, and for this reason all freedom is will, but not all will is freedom. 108


37:89 Alfarabi, The Gems of Wisdom, in Collection, op. cit., pp. 147-152. See also Political Regime, op. cit., p. 47-51; The Sources of Questions, in Collection, op. cit., n. 20, p. 74.

38:90 Alfarabi, The Gems of Wisdom, in Collection, op. cit., p. 149; see also: Alfarabi, Political Regime, op. cit., pp. 47-51.

38:91 St. Thomas. Summa Theologica. Part I, Third No. (QQ. LXXV-CXIX)-Q. LXXVIII, Art. 3, p. 80. Tr. by the English Dominican Fathers.

39:92 St. Thomas, Summa Theologica, Part I, Third No. Q. LXXVIII, Art. 4, p. 85.

40:93 Alfarabi, The Gems of Wisdom, in Collection, op. cit., p. 152.

40:94 Alfarabi, The Intellect and the Intelligible, in Collection, op. cit. n. 3, p. 47.

41:95 Albertus Magnus, An. post. I,. 1, 3.

41:96 D Alfarabi, The Intellect and the Intelligible, in Collection, op, cit. n. 1, pp. 45-46.

41:97 Alfarabi, Ibid. op. cit. n. 2, p. 47.

42:98 Alfarabi, Ibid. op. cit. n. 3, p. 47.

42:99 Alfarabi, Ibid. op. cit. n. 4, pp. 47-48.

42:100 St. Thomas, Summa Theologica. Part I, Third No. (QQ. LXXV-CXIX),-Q. LXXIX, Art. 2, p. 92.

43:101 Alfarabi, The Intellect and the Intelligible, op. cit., n. 5, pp. 49-54.

43:102 St. Thomas, Summa Theologica, Part I, Third No., Q. LXXIX, Art. 3, p. 94.

43:103 St. Thomas, Summa Theologica, Part I, Third No., Q. LXXIX, Art. 4, ad. 4, p. 98.

43:104 Alfarabi, The Intellect and the Intelligible, op. cit., n. 6, pp. 54-56.

43:106 With regard to the acquired intellect, see Albertus Magnus, Summa Theol., parag. II, Tract. XIII, Quaest. LXXVIII, Membr. 3.

44:105 St. Thomas, Summa Theologica, Part I, Third Number, Q. LXXXV, Art. 1, ad. 4, p. 183.

46:107 Alfarabi, Political Regime, op. cit., p. 65. See also pp. 50-51.

46:108 Alfarabi, A Letter in Reply to Certain Questions, in Collection, op. cit., n. 31, pp. 107-108.

Next: Chapter IV. Ethics