Sensus Communis

 

 

We shall not cease from exploration

And the end of all our exploring

Will be to arrive where we started

And know the place for the first time.

(T. S. Eliot, 'Little Gidding')

 

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That with which people most continuously associate - the discourse (logos) that orders everything - with this they are at variance; and what they encounter every day seems strange to them.

 

Although the discourse is shared (xunou), most people live as if they had a private understanding.

 

The person who speaks with understanding (xun nooi) must insist upon what is shared (xunoi) by all, as a city insists upon its law.

(Heraclitus, DK 72, 2, 114)

 

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THE ROLE OF SENSUS COMMUNIS IN ARISTOTLE, THOMAS AQUINAS, LOCKE AND KANT

 

a NICE thesis!!! by Albert Ichiro Suzuki

https://open.bu.edu/bitstream/handle/2144/6318/Suzuki_albert_1952_web.pdf?sequence=1

 

A.  The Inner and the Outer

 

Philosophy [for the early Greeks][1] consisted in two main divisions:

 

(a)          Epistemology (logos tes epistemes), the doctrine of knowing,[2]

and

(b)          Ontology (logos ton ontos), the science of that which truly is.[3]

 

Of these, the latter, [Ferrier maintains,] comes first. Human reflection looks outward before it looks inward and consequently cosmological inquiries into the nature of the physical world preceded inquiries into the way in which knowledge of the physical world is acquired.

 

[....] In early Greek thought, [....] cosmological inquires centered around the attempt to discover a "material principle" or "cause" from which every living thing (i.e., animated things; the concept of which involves the animal kingdom as well as the vegetable kingdom [4]) and nonliving thing originated. But gradually epistemic problems came into prominence among Greek thinkers, and it may be said that Socrates was the first who set the current of Greek thought definitely in this direction. [??? – Parmenides? Heraclitus?]

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1. The term epistemology which derives from two Greek words of episteme (knowledge) and logos (science) was used for the first time by Ferrier. [Ferrier, James F., Institutes of Metaphysics [IOM]. Edinburough & London: W. Blackwood, 1856.]

2. Ferrier, IOM, 48.

3. Ferrier, IOM, 47.

4. Lucretius and Cicero distinguished animus (mind) from anima (life or the living). Lucretius, De rerum natura, III, 133-160; Cicero, Tusc., I, 19-22.

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B. Sensation and Intellect.[1]

The study of the cognitive powers was first attempted by the early Greek materialists who tried to interpret the physical world in its relationship to the subject. The soul had been conceived by the early philosophers as the cause of life in the body and also, after they began to reflect on the subjective powers, as the cause of sensation.

 

Such notions that there are visible things such as eidola which flow off from an object, similar in shape to the objects from which they flow and fall into the eyes of the persons seeing, resulting in sight, were held by Leucippus and Democritus. All sense experiences were reduced to the atomic sensationalism of actual 'touch' of soul-atom and atoms of the external objects.[2]

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1. It is said that Alcmaeon of Crotona distinguished sensibility from sense-perception (aisthanesthai) from intelligence (to eunienai), and to have confined the possession of the latter to human beings. cf. Beare.

2. Aristoteles, Sens., 442b.

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This atomic interpretation of the inner-outer relationship was helpful for the physical explanation of sense-experience in space. But it could not solve the temporal aspect of psychic phenomena such as the preservation and reproduction of images acquired by the individual sense-organ. This process requires much greater and more complex activity of the mind which combines or discriminates those images. Plato was the first great exponent of the rationalistic method in this field. From the criticism of sense-experience, which is rather relative, he regarded part of knowledge as dependent upon sensation and part as due to the ideas that are in the mind from the beginning. For him sensations must be supplemented and corrected by the ideas innate in the soul, before they give true knowledge. However, Plato's ideas were the prototypes of things that exist before objects in the universe or in the mind of God and were regarded as part of the original endowment of the soul before any experience. This assumption was the basis for Plato's moral doctrine as well as his epistemology. He tried to show that the sensible world was derived from the world of Ideas.

 

Aristotle, on the other hand, was an empiricist [???]. He started with a definite observation or group of observations and developed his general principles from them. And from these series of observation of various theories as well as of his own “thought experiment,” he separated Platonic modes of apprehension from the realm of the object of knowledge. According to Hammond,[1] Plato's faculties of the mind "depend upon the reciprocal relation between subject and object." Though Aristotle's account of the theoretical activity of the higher faculties of mind is very meager and not complete in itself, we must admit that he was the first who tried to describe the Platonic distinction between animal knowledge and the rational knowledge of man in terms of faculties.[2] And it was the combination of the Platonic doctrine of the relationship of “Being  and  knowing” and the Aristotelian conception of the biological powers of the mind that developed into the edifice of the later Scholastic anthropology of Thomas Aquinas and others. [2]

 

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1. Hammond, AP, xxvi. Also in xxvii he says, "Plato's entire psychology,  in which the soul's parts are separated into existentially distinct units with distinct anatomical organs is ethico-teleologically determined; the soul is a unitary life functioning in distinct modes or faculties. It is a single indivisible mind expressing itself in nutrition, sense-perception, imagination, memory, reasoning. 

2. "In some oreatures, as we have said, all of the above mentioned psychic powers are found, in others some of them, and in still others only one. By powers we mean here the powers of nutrition, appetite, sensation, movement in space, and of rational thought." Aristotle, De Anima, 414a 31. 

3. Even in the Kantian system, especially in his pre-critical writings, we can observe the influence of Scholastic psychology.

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A. The Conception of Sensus Communis.

 

The term, sensus communis, is a translation of koine aisthesis [1] which was used first by Aristotle for the faculty of synthesis which was referred to sense. It was the Arabic translators and commentators [2] who used the term, sensus communis, which involved the psychical processes, such as imagination, fantasy and memory.

 

The sensus communis is regarded, by Thomas Aquinas, as one of the powers of the sensus interiores in relation to the powers of Imagination, memory and sense-judgment (vis aestimativa), etc. But until Thomas Aquinas analyzed the connotations of the term, most of the commentators of Aristotelian psychology interpreted sensus communis in a much wider sense including the whole psychical processes except the so-called five senses.

 

It is necessary here to consider how much of what Aristotle had to say regarding it was to be found in the speculations of his predecessors. However, since they did not undertake the discussion of the faculty of synthesis as such, we must satisfy ourselves with stating the functions which were ascribed by Aristotle to the sensus communis, and seeing how these functions are dealt with by preceding psychologists.

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1. Aristotle seldom uses this actual term (cf. 425a 27; 450a 10; 686a 31), often employing equivalents like primary sense [to proton aisthetikon] and judging sense [to koinon].

 

2. Especially Avicenna (979-l037 A.D.) and Averroes (1126-1198 A.D.).

 

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To this department of the mind Aristotle assigned:

 

     (a) the power of discriminating and comparing the data of the special senses, all of which are in communication with this power;

 

     (b) the perception of the 'common sensibles,'  (to koina) of which the principal are Movement, Form, Number, Magnitude and Time;

 

     (c) the consciousness of our sensory experiences, i.e., the power by which we not only perceive, but perceive that we perceive;

 

     (d ) the faculty of imagination, i.e., reproductive imagination (to phantastikon);

 

     (e) the faculty of memory and reminiscence (mneme kai anamnesis)

 

     (f) the affections of sleeping and dreaming.

 

 

As to the conception of the synthetic faculty [1] (involved in (a), (b) & (c)) which was not distinctly formulated until we reach Plato, the interpretations of the Greek “materialists” on sense perception should be noted.

 

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B. The Background of Aristotle's Sensus Communis

 

(l) The Interpretation of Greek “Materialists”

 

As mentioned before the early Greek thinkers who are called philosophici naturales by the medieval philosophers sought for the principle (arche, principium) or an elemental substance from which every  living and non-living thing was composed. Their principles, such as Thales' water, Anaximander's 'boundless' or 'unlimited' (apeiron), were the principles of all existence - including all living things. Their philosophy is called “hylozoism,” i.e., the doctrine of the unity of matter (hyle) and life (zoon),[1] according to to which matter is by nature endowed with life, and life is inseparably connected with matter.

 

Probably they might have tried to explain the activity of human soul from a hylozoistic standpoint, but no further data about the relation of sense perception and the sensus communis can be available from the extant fragments of these philosophers.[2]

 

Some passages of Heraclitus (fifth century B.C.) who held that all knowledge comes to man “through the door of the senses,” and Protagoras (c. 484-411 B.C.) who maintained that the entire psychic life was made up only of sensations, tell us that they turned their eyes from the outer world of nature which, according to that, is nothing but flux, to the inner world which is a receptacle of the relative experience of the flux coming through the sensation.

 

The more empirical and consequently materialistic studies of the mind can be observable in the theories of Empedocles (c. 490-435 B.C.), Democritus (c. 460-370 B.C.) and a little later in the writing of Epicurus (c, 341-270 B.C.). They did not doubt the existence of the objects in the external world which give off from their surfaces, or pores, effluvia (Empedocles) or which projected faint images, or eidola (Democritus and Epicurus) to the mind. For them, especially for Epicurus,[1] sensation is irrational (alogos) and therefore does not admit of proof.[3]

 

In De rerum natura, Lucretius, the follower of Epicurus, describes his master's doctrine, in which he explains some of the faculties of the mind which were attributed to the power of sensus communis. For Epicurus the fundamental criterion is sensation (aistheis), "we must keep all our investigations in accord with our sensations," ''the criteria of truth are the sensations and concepts and the feelings."[1] Sensation is the ultimate and only criterion of truth.

 

You will find that the concept of the true is begotten from the senses at first, and that the senses cannot be gainsaid.[2]

 

Taking it for granted that sensation transmits to us the notities veri, how can we interpret the various sensations given by the different organs as a unity or as a manifold? To see a street-car coming and to hear its noise are two different experiences through the two sense organs of ear and eye. Or again "to see” and "to perceive that I see” are also different experiences. Epicurus refuted the possibility of sensus communis as the principle or faculty of the synthetic power of the mind which combines those various sense-experiences received from the outer senses:

 

Will the ears be able to pass judgment on the eyes, or touch on the ears? Or again will the taste in the mouth refute this touch; will the nostrils disprove it, or the eyes show it false?[3]

 

No, because each sense has its proper faculty set apart from the other; each has its own power.[1] But

 

if you do not accept communis sensus, there will be no standard by which we can reach the truth about hidden things.[2]

 

In saying sensus communis, however, Lucretius meant rather the general concept which was first given through the sensus proprii (five peripheral senses) and apprehended as unity (which Epicurus called 'anticipation,' prolepsis). He was not thinking of any independent faculty of sensus communis in the Aristotelian sense of the word.

 

For Epicurus, the image of sight, for instance, after having been perceived by the eyes, passes on into the mind and is there stored up and can be recalled in the act of memory. Moreover, when we have had a number of such images of any one class of things, they unite in a kind of 'composite photograph'[3] of the object and so form a general conception or 'concept' of the thing, to which we can refer as a test afterwords.[4] The reason why Epicurus called this general concept by the name of 'anticipation' is because it enables us to anticipate the appearance of something and to give it a notion which was acquired by a series of sensations of things which belong to the same species. This might be not absolutely true. But it has a derived truth founded on sense experiences which are immediate and, therefore, direct truth, though alogos.[1]

 

The great asset which was bequeathed to the philosophy of Aristotle by these empirical materialists was the notion of 'Nihil est in intellectu quod non prius in sensu,'[2] which is peculiarly shared with the psychology of Stoic philosophers in their theory of 'tabula rasa.' But they avoided the argument of how those sensible objects are acquired through senses in our mind as images or ideas or as concepts. In other words, neither a psychological study of these faculties of the mind nor an epistemological study of the conditions or forms or sense-perception were done by these materialists.

 

In short, we can point out some of their views concerning sensus communis as follows:

 

(a) They did not discuss the faculty of synthesis by which the data of sense are combined and distinguished, by which we are conscious of our mental acts, and by which we imagine and remember.

 

(b) They did not draw any dividing line between sensibility (aisthesis) and intellect (nous) as psychical entities. But a bipartite division of the soul: of to logikon (which is placed in the thorax) and to alogikon which is distributed all over the body), in Democritus, seems to have anticipated the tripartite division of Platonic psychology.

 

c) Their notion of phantasia is not the power of reproduction, but merely the 'presentative' faculty, by which things appear, or present themselves, to us in ordinary perception. Democritus even held that the 'secondary qualities' (as they were called by Locke) have no objective existence: they are only affections of our sensibility according as it is qualitatively altered.[3]

 

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1. Bailey, GAE, 384.

2. Aristotle, De anima 432a 7. Also "sense is receptive of sensible forms apart from their matter, as wax receives the imprint of the signet-ring apart from the iron or gold of which it is made.”

3. Aristotle, De anima, 424a 17ff.

 

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Aristotle

 

A. Development of the Conception of “the Common.”

 

The notion of “the Common” (to koinon) in Plato's psychology was enlarged by Aristotle to the conception of “common sensibles”[1] to signify a specific aspect in the psychological process of sense-perception. For Aristotle, the act of sense-perception is not completed in the peripheral five sense-organs, but only in the “central sense" (to kurion aistheteron). These are five peripheral organs of sense: eye, ear, tongue and throat, nose, skin and flesh. These are stimulated by objects in the external world which by contact with the organ work some change (alloiosis) in it.[2] The contact is effected

 

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1. Aristotle, De Anima, 418a, 425a 12, 426a-427a; Somn., 455a 21; De long., 467b 28; Sens., 449a; De mem., 450a; De juv., 467b.

 

2. It was in this sense that later medieval thinkers named these peripheral organs of sense as "exterior” or “external”because of this immediate cont”act with the objective world. But Aristotle employs, more faithfully to his doctrine of psychological faculties, as “special sense” (idia aisthesis) which has translated into Latin as “sensus proprius.” Both Aristotle and Thomas Aquinas employ both singular and plural forms for the expression of proper sense, exterior sense, interior sense, but not for common sense, although Aristotle uses the term, common sensibles in plural.

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through a medium which transmits a stimulus from the sense-object to the perceiving organ, and the change which the stimulus works in the peripheral organ is further transmitted by the blood or sense-duct to the sensorium (central organ).

 

On examining the psychology of Aristotle, three factors are to be taken into account in each stage of sense-perception:

(a) the organ,

(b) the object or thing sensed,

(c) the medium of transmission.

 

In the case of visual perception these factors are the eye, the thing seen and the diaphanous or translucent medium, whether the latter be liquid or atmospheric. [1]

 

To each of the individual senses belongs the functions of apprehending a particular quality (idion aistheton).[2] In vision, only color is sensed; in hearing, only sound; in smell, odor; in taste, flavor and in touch, the qualities of body as body (hardness, etc.). These are all sensation-qualities, but they are not percepts (i.e., the perception of the object as a whole). By means of sight, e.g., we have the sensation of' green, but not an olive itself. An olive is a percept, green is a sensation. An olive is made up of several ideas, of hardness, taste, color, form, magnitude, etc., and these are unified in a particular thing and they constitute it a single concrete object, "olive." The peripheral organs of touch, taste and sight furnish us with several ideas or qualities belonging to a concrete thing. Thus each single sense judges (krinein) of its proper object and is not

 

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1. This physical explanation of vision and other sense-organs is almost entirely bequeathed from Atomistic views of Empedocles and Democritus. Only their material theory did not really touch the problem which they had set out to solve; it establishes a connection between object and percipient, but it does not really tell us what thought and sensation, as we know them, are. cr. Bailey, GAE, 164.

 

2. De anima, 418a 10ff.

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deceived as to the fact that there is a color or a sound. [1] But in order that these various qualities are brought together for knowledge and seen to inhere in a single object, it is necessary to think of some unifying function which is called by the names of the central or common sense; it is only then that a percept is formed in our mind. The function of sensation, therefore, belongs to the peripheral or external senses in so far as they mediate the qualities of an external object to the inner sensorium or common sense. And perception[2] is one of the functions of the central sense.

 

B. The Common Sensibles.

 

In the second chapter of De Anima[3], Aristotle describes three different sensible objects: two of which are perceived in themselves or directly. While the third is perceived per accidens or indirectly. Of the first two the one is the special object of a particular sense, the other an object common to all the senses. i.e., the object of perception, or common sense. And he employs the term "common sensibles" (koina aistheta) for the objects of common sense.

 

According to Aristotle, these common sensibles are (i) motion, (ii) rest, (iii) number, (iv) figure or form, (v) size or magnitude and (vi) time. These qualities are not the special objects of any single sense, but are common to all.

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1. De an., 418a., 410a. 41Gb and 429a, 432a.

2. Sens., 449a 3ff.

s. De an., 418a 7ff .

4. De an., 418a 17, 426a 14-30; De mem., 450a 10.

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For example, a particular motion can be perceived by touch as well as by sight. In De sensu,[1] Aristotle adds roughness, smoothness, and sharpness and bluntness in solid bodies a the common function of sight and touch.[2] The statement is quite true of number and unity:[3] each sense perceives “one” object, and number is made up of units. It is also true of motion. But magnitude and figure can hardly be said to be directly perceived except by sight and touch. The fact is that not one of these common sensibles is perceived by one sense only; and all the senses, in various combinations, at one time or another contribute to make them known.

 

In comparison to Aristotle's conception of the common sensible Plato's conception of the common notions (ta koina) which are put in pairs of 'being' and 'not-being'; 'likeness' and 'unlikeness'; 'identity' and

'difference'; 'unity' and 'plurality'; the 'odd' and 'even', etc.,[4] indicates that he was thinking of a much higher structure of mental activity. For Plato these common sensibles are not perceived by sense but directly apprehended by soul itself - which may be indirectly apprehended by Aristotle's intellect, though directly by sense.

 

C. The Functions of the Sensus Communis.

 

(i) As a power of apprehending the common sensibles.

 

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1. De sensu, 442b 5.

2. cf. Locke's primary qualities: space or extension, figure, rest, and

motion. Locke, ECHU, 158.

3 . De anima, 425a 19ff.

4. Eth. Nic., 1142a 27; Plato, Theaetetus, l86a.

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As it is shown above, for Aristotle, the apprehension of "the common" must be done by sense, because they are sensibles.[1] And they are not apprehended by the particular senses like sight or touch, but by the common power that is associated with all the particular senses (tini koino tog aistheterion apanton)[2]

 

(ii) As a power of self-consciousness.

 

We also recognize particular sensations as belonging to ourselves and can hold them up before our minds as something known to us. We know that we see. We are conscious that we see and hear. In other words, we are conscious of a sensation. It is, according to Aristotle, by means of the central sense. Thus, consciousness [3] comes to be another function of the common sense.

 

(iii) As a principle of the unity of sensation.

 

As is mentioned above, in every sense there is a power which is peculiar to it and another power which it has in common with others, i.e., a kind of common power that is associated with all the particular senses by virtue of which we are conscious of our sensing and discriminate sensations from each other. Thus, sensation is unitary and the master-organ of sensation is unitary. [4]

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1 . De anima, 426b 15. However this argument is falling into petitio principi. This does not give any proper reasons why the apprehension of the common must be in the function of sense-perception rather than in intellectual activity.

2. Somn., 55a 3. Here Aristotle interprets sleeping and awaking as an affection (pathos) of this common sense and he attributes common sense to the faculty of sense rather than to the intellectual power, because sleeping and awaking are found in all animals . But still this is not a proper reason for assuming that common sense is a sensitive faculty.

3. De anima, 425b 12ff; De sens., 455a 15ff .

4. Somn., 465a.

 

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However, according to Aristotle, this does not signify the existence of an independent sense-organ beside the proper senses, but rather it is a principle or 'form' which lies under each proper sense, giving them unity and makes them possible to start their own sensitive activity. It was in this sense that Aristotle called common sense as “the first sense” (to proton aistheterion)[1] or “the central sense” (to kurion aistherion), and the faculty of common sense as “the first power of perception” (to proton aisthetikon) or “principle (beginning) of sensation” (arche tes aistheros).[2] Concerning this point, an explanation of Thomas Aquinas will be adequate:[3] "The interior sense is not called common by predication, as if it were a genus, but as the common root (communis radix) and principle of the exterior senses.” This function of the common sense is very important. Because this is not gained by the inductive analysis of the common sensibles but comes to be apprehended as formal condition of all sensitive activity, though Aristotle did not refer to it.

 

(iv) As a Discretionis Principium.

 

The individual senses furnish us with color, sound, etc., but

 

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1. It is in this sense that Locke employed the term, primary qualities.

2 . Somn ., 456a, 458a, 464a; mem., 450a, 451a.

3. "Sensus interior non dicitur communis per praedicationem, sicut genus, sed sicut communis radix, et principium exteriorum.” Thomas Aquinas, Summa theologia, I, 78, 4, Resp. ad primum.

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it is not their function to discriminate, between sweet and white, or to differentiate degrees of bitter. This is a function of judgment, [1] and it is ascribed by Aristotle to the common sense. The discrimination between true and false, between real and unreal in our perceptions is made not by the peripheral senses, but by the central sense. The sensation, because it is only a fact and as a sense-process pronounces no judgment, is always true [2], but when the sensation is predicated of something and a judgment is expressed, error is possible. It is the internal or central sense that performs this office of judgment in the share of perceptual knowledge, and it is, therefore, to the central sense alone that, strictly speaking, truth and falsehood in this sphere can be ascribed.[3]

 

(v) Other Functions of the Sensus Communis.

 

Further, sleep,[4] imagination,[5] memory,[6] and dream,[7] in so far as they signify the interruption of consciousness or the continued life and movement of residual sense- perceptions, are functions of the sensorium, or central sense.

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1. De anima, 426b 14ff. cf. Thomas Aquinas, Sum. theol., I, 78, 4, Ad secunum: “Wherefore the discerning judgment (discretionis principium) must be assigned to the common sense; to which, as to a common term (sicut ad communem terminum) all apprehensions or the senses must be referred; and by which, again, all the intentions of the senses are perceived; as when someone sees that he sees."

2. De an., 427b 11 ; 428a 12.

3. Thomas Aquinas distinguished animal judgment (vis aestimativa sive intentiones) from human reasoning power (vis cogitativa). Sum. theol. I, 78, 4. Respondeo.

4. Somn., 454a 23; 456a 1.

5. Insomn., 460b 17.

6. Mem., 451a 17.

7. Insomn., 458b 1.

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In summarizing these various functions of the central or common sense, we can point out the following eight:

 

(1) The cognition of the "common sensibles," i.e., motion, rest, number, figure, size, time , etc.;

(2) The unification of the primary sensibles, or the complete set of sense perception;

(3) Consciousness, or the perception that we perceive;

(4) The suspension of consciousness, or sleep;

(5) Judgment, in so far as judgment applies to the comparison, contrast and discrimination of the deliverances of senses;

(6) Imagination, or residual sense-images;

(7) Memory (including reminiscence) or the voluntary and involuntary reproduction of sensations; and

(8) Its content as the potentiality of reason.

 

D. The Perception of Time.

 

For Aristotle, Time is perceptible. There is no imperceptible time.[1] In De Sensu he deals with the problem of the possibility of experiencing two simultaneous sensations at one and the same moment of time. This is in the discussion of the power of the fusion of sensations in the sensus communis.

 

When one perceives one's self or something else in continuous time, it is impossible for one to be then unconscious that one is; but if there is in continuous time a moment of such duration that it is altogether imperceptible, it is evident that one would then be unconscious of one's own existence, or would not know whether or not one sees and perceives.[2]

 

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1. De Sensu, 448B 15.

2. De Sensu, 448a 20- b 5.

 

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Thus the perception of time is closely related with self-consciousness. And he explains that the perception of temporal duration is only possible in spatial extension or movement or numerical series. Further, he raised a question about the relation of consciousness and several simultaneous sensations:

 

Is it possible that the sensations be simultaneous in the sense that they are experienced in different parts of the soul, and not in one indivisible part, though by parts which are indivisible in the sense of forming a continuous whole?[2]

 

Here Aristotle enumerates a series of these questions such as the perception of the different colors in one object as a whole, or the perception of the same object which comes through two eyes, etc. [3] And he concludes that there must be some unitary principle in the soul, whereby it perceives things as wholes.[4] And this function is ascribed to the “common sense," where the various experiences of the individual senses are fused into a whole or the percept. Thus the notion of “simultaneity” is closely related with the conception of the synthetic power of the soul. Thus Aristotle asserts that regardless of the presence of our consciousness, time as such exists.[5] But the perception of time itself derives from the combined experiences of perception of the present, expectation of the future and memory of the past.[6]

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1. De Sensu, 448a 20-b 5.

2. De Sensu, 448b 18-20.

3. De Sensu, 448b 21-449a 2.

4. De Sensu, 449a 11-12.

5. De Sensu, 448b 15.

6. Mem., 449b 10-15.

 

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Therefore memory and time are perceived by the same organ.[2] And the organ is the central organ or heart.[3]

 

Also Aristotle defines time as the measure or number of motion, but time cannot exist apart from mind, as number cannot exist apart from a calculator, and the sole calculator is mind.[4] At the beginning of De Anima , Chapter Three, he tried to reduce all the common properties to motion.

 

All these properties we perceive by means of motion, e.g., magnitude is perceived by motion. Form is a sort of magnitude, and rest we perceive from the absence of motion. Number is perceived by the negation of continuity [...][5]

 

From these we can understand the following items based on Aristotle's conception of time:

(1) Time is the measure or number of motion. And motion is a fundamental quality of common sensibles.

(2) Time cannot exist apart from mind. When we perceive something, we perceive it as a present perception or as a past recollection or as a future expectation. Time cannot be separable from human consciousness.

(3) There is no imperceptible time, though we can be unconscious of it.

(4) Time is perceived by the common sense, because the perception of time is included in the perception of the common sensibles.

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2. Mem., 449b 10-15.

3. Mem., 451a 17.

4. Phys., 219a 10; 223a 16; De coelo, 279a 14.

6. De anima, 425a 18-20.

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Conclusion to this chapter.

 

For Aristotle, the aim of all science is to form an intelligible universe by discovering the universal in the particulars – particulars which are the primary and only substances or existences, but which have no existence apart from the universal which is their "form" or the class (kind) of their existence. Such universals are concepts formed by the intuitive reason on the basis of repeated "sensation,” which rise to “memory,” and then to "experience," of the same kind of thing.

 

Then how about the conceptions of psychic activities? Are they also the “forms"? But the "forms" are acquired by those psychic activities. If they are forms, they are the forms which must be acquired by the same forms. Thus Aristotle's analysis of the common sensibles leads to the notion of consciousness. At the same time, the common sensibles can be perceptible by means of motion, the measure and number of which is, for Aristotle, time.

 

Thus he noticed that those three, consciousness, time and the power of sensus communis are inseparable and acquired by our experience. And, as he tried to define the peripheral senses by the organic functions, so he sought for the function of sensus communis in the physical organ. But neither his biological attempt at localizing “sensus communis” nor that of describing it in the metaphysical terms, were successful. However, we cannot deny that his analysis of sensus communis opened a new field in the study of sense-perception.