1942. Plotinus’ Theory of Sensation.
The Philosophical Review Jul.
Plotinus’ Theory of Sensation1
Und wei haben wir uns die Erscheinungen dieser Einheit, die sinnliche Empfindung, die Begierde u. s. f. zu erklaren? Diese Fragen waren fur Plotin nicht ganz leicht zu beantworten, denn durch seinen einseitigen Spiritualismus hat er wirklich die Mittel zu ihrer genugenden Losung abgeschnitten.2
Zeller has expressed the problem well. The grandiose structure of Platonic spiritualism requires a plausible theory of sensation. Unless the ideal world and the sensible world can be united, Aristotle's criticism that the Ideas are a useless duplication of objects will be justified. Whether or not Plotinus by a one-sided spiritualism cut himself off from a real solution, whether or not his whole philosophy is, as Paul Elmer More says, "a meaningless answer to an impossible question raised by a gratuitous hypothesis," it cannot be asserted that Plotinus was bling to the problem. In every Ennead except the second, the primary subjects of the tractates force his consideration of sensation and of the relation of the sensible world to the world above. As he was not blind to these difficulties, neither was he so unsuccessful of solution as to write in vain - if to write in vain means to lack influence. Not only did his pagan followers continue the Platonic tradition till the end of antiquity, but in his own city of Rome Augustine utilized the considerable amount of what looked promising to him and transmitted to a new era some of the ancient wisdom.
Because the theory of sensation was a part of Augustine's borrowings, and because of its strategic importance to the justification of spiritualism, one would expect that historians of philosophy had by this time produced many and prominent dissertations on the subject. Such, however, is not the case. Granted that there is no good reason to disparage Dean Inge's monumental work on The Philosophy of Plotinus, it is a mere matter of fact that sensation proper is disposed of in four pages, plus another page for pleasure and pain. Brehier's one-volume work of the same title, while it has a good paragraph on memory, treats sensation only incidentally.
This neglect - of course Plotinus can furnish Inge and Brehier with an unmanageable amount of material on other subjects - is not to be accounted for by the meagreness of reference in Plotinus. The embarrassment comes in coordinating the wealth of reflection. A survey of this wealth indicates that such a coordination is most naturally attempted under the four following headings: (1) The Objects of Sensation; (2) The Process of Sensation; (3) The Body and the Soul; and (4) Utility and Knowledge. At many points digressions on more general Neoplatonic principles might be expected. The theory of sensation has its bearings on aesthetics, ethics, and the mystic vision of the One. But to commence to fill in this sort of explanatory background removes the possibility of any proximate conclusion. The attempt has been made, therefore, to restrict the discussion to positive psychology and the barest minimum of epistemology.
The Objects of Sensation
Plotinus, in his reaction against Stoic materialism, produced a system that may conveniently be called spiritualistic. This term, however, when loosely used, can give rise to erroneous prejudgments as to the nature of the objects of sensations. For example, Charles Boyer seems to suggest that the sensible object is a creation of the individual human mind.3 Or, if this reduces to an un-Platonic solipsism, someone might possibly be tempted to look for Berkeley's expedient of having God produce the object in the mind of the individual. Or, perhaps, in the historical situation, Plotinus under Aristotelian influence may have developed a non-materialistic impression of some Ding an Sich.
It was not only the Epicureans and the Stoics who explained sensation as the reception of impressions; Aristotle did so too. They differed, of course, in that the later two schools used the word impression in a literal or at least a physical sense, whereas Aristotle's usage was metaphorical. Since Plotinus frequently profited by Aristotle's contributions to philosophy, it is natural to look for Aristotelian influence on this point also.
Attractive though this suggestion may be, it must be judged incorrect. In his tractate On Sensation and Memory4 Plotinus holds that the metaphorical impression of Aristotle and the materialistic impressions of the other schools are alike refuted by the same considerations. The concluding phrase of this tractate, by noting that the difficulties in explaining sensation as a result of impressions are met neither by those who consider the soul a body nor by those who make it incorporeal, indicates that Plotinus was not limiting his criticism to materialists. In addition to this concluding phrase, there are through the tractate several references to Aristotle's De Memoria, and this is sufficient to show that he has Aristotle also in mind.
The first argument of the tractate to prove that sensation is not an impression on the soul is that we see an object where it is, that is, at a distance from us, and not in the soul as an impression would be.
Zeller emphasizes the point that there is no impression in the soul but only in order to make the sensible object and impression in the body, perhaps a physiological change in the retina. Some texts, as might be expected, do not seem at first sight to rule out the notion of a bodily impression. For example, when in two passages5 Plotinus asserts that sensation knows only external objects, he adds that even if we sense a pain inside the body, it is an object external to the soul. But the implication of the passage is not so much that sensible objects are within the body in the form of perceptions of physiological changes; but rather than the large number of sensible objects, to which pain forms an exception, are external not only to the soul but to the body as well.
Plotinus also says that the soul looks outward, and that there would be no need of looking outward if the soul contained in itself the form of the object. Superficially this would not rule out the notion of a bodily impression. The mention of distance, however, is more easily understood as incompatible with the identification of the sensible object and an impression on the organ. For the distance referred to is neither a metaphorical distance from an illocal soul, nor a literal distance from a materialistic soul, but a distance from the sense-organ. An object in contact with the pupil of the eye cannot be seen. From the necessity of distance between the eye and the objection Plotinus concludes that there is an even greater necessity to deny that the soul sees an impression stamped on itself. If the soul were stamped as with a seal, it could not see the stamp, for the seeing soul and the seen object must be two distinct things. If per impossibile the soul could see a form contained in itself, it would be unable to assign a distance to the object. And further, how could the soul say how large the sky is, or even say that the sky is large, when it cannot receive an impression of such a size.6
Is sensation were like an impression on wax, then, to mention another consideration, all sense-impressions, since they would be in the same soul, would presumably be materially similar, and there would be no possibility of distinguishing an auditory from a visual impression.
Again, if memory were the preservation of sense-impressions, one could not first forget and then remember; the impression would have to remain in the soul, or, if it disappeared, another sensation would be required to impress the soul anew.
But the chief reason for rejecting the theory that what we perceive is a perception or impression is that in such a case we could not perceive the things themselves; shadows are all that we should grasp. This seems to be the chief reason because, by analogy with the higher functions of mind,7 it is essential to the dogmatism and realism that Plotinus is offering as a substitute for the previously popular skepticism.
Despite the fact that Plotinus so clearly rejected even the Aristotelian form of an impression-theory, Zeller writes: "Nicht die sinnlichen Dinge selbst sind es, die von der Seele wahrgenommen weden, sondern nur die Eindrucke, welche die Dinge auf ihre Sinnlichkeit hervorgebracht haben."8 Zeller refers to the following lines for support. "The soul's power of sensation does not grasp sensible objects, but rather the impressions that arise in the living being through sensation; for these impressions are already intelligible objects [νοητα ]."9 To this passage Zeller might have added this: "Even granting that what sensation grasps in the sensible object, that which is known by sensation is an image of the thing, and sensation does not grasp the thing itself, for this remains outside."10 Since, however, this may be an ad hominem remark addressed to the Epicureans, it will be of no weight if the passage from the first Ennead can be explained.
The seeming discrepancy arises because of the ease with which Plotinus adjusts his perspective. The passage in question does not describe literal sensation at all. Just as, in the general view of the universe, the stone and trees of this ordinary world are images of realities in the divine mind, so also literal sensation is an image or reflection of a higher mental activity. Although in strictness this higher activity should be called intellection, or at least discursion, still it is permissible to speak of it as perception or even as sensation. It is in light of this principle that the quotation Zeller makes from the first Ennead must be understood.
The relation of the soul to the body, which underlies that passage, is somewhat complicated. Plotinus at the beginning of the tractate had asked the question: Is the seat of pleasure, fear, and desire the soul alone, the soul using a body, or a third thing produced from the two? The answer definitely excludes any mixture of soul and body, not so much because mixture is a physical concept inapplicable to soul, as because Plotinus wishes to preserve the closest possible connection between our soul and the world soul. Necessary for understanding Zeller's quotation are the words that open the chapter.
The composite [living being] exists because of the soul's presence; but the soul does not give herself as such to the composite or to its element [the body]. But from a definite kind of body and something else like light that is given off from her, the soul produces a different thing - the nature of the living being. Of this nature, perception and all the other passive states of a living being are to be predicated.11
Thus the soul does not dwell in the body; it remains apart and sends a representative, so to speak, its image. In the Plotinic system, then, it is this nature that functions as the soul is supposed to function in the more common view of things. This nature forms the mysterious connection between physical or chemical changes in the body and the purely spiritual conscious perception that leads to intellectual heaven. Plotinus then goes on to ask how, in view of the role of nature, can it be said that we, the real we, the higher soul, perceive? He answers that there is a connection between soul and nature, and then in the words quoted by Zeller speaks of perceptions for the soul. In these lines, therefore, one must not see an assertion that sensation, a function of the living body, grasps only impressions in the body; the correct explanation is that the higher form of sensation, the activity of the soul as distinguished from the function of nature, does not grasp sensible objects, but indeed directs its attention to intelligible objects, which somehow have followed upon literal sensation. While the general principle of this explanation appears in many other passages, Zeller ought to have taken warning from this passage itself. The words that immediately follow the phrase "For these are already intelligible objects" are "with the result that [or because = ως] external sensation is its image, while it itself, in reality the truer, is the impassible contemplation of forms."
The bolder interpretation of Boyer that the soul creates sensible objects is likewise untenable. He had attempted to support his position by the lines: "In the same way the soul is connected with sensible objects, and of her own power makes them shine, as it were, and puts them before the eyes; for her power is suited to give birth with reference to them."12 But this passage does not show that the soul creates or gives birth to memory; she gives birth with relation to the sensible objects.
If these arguments serve to rule out the theory of impressions, and, with the epistemological, indeed the ontological, demands of realism, establish the necessity of external objects for sensation, a short reference in conclusion may complete the precautions against understanding spiritualism in any Berkeleyan sense. "Intellect," writes Plotinus, "is not related to its objects as sensation is to the sensible objects that are prior to it. Intellect is its objects."13 If, therefore, the objects that are seen are prior to the faculty of sensation, they cannot depend on any subjective process. In relation to an individual person, they are real, objective, and external.
The Process of Sensation
With the relative independence of the sensible object established, the next problem is the description of the manner in which sensation takes place.
The solution to this problem may be classified under two chief heads: mechanistic and non-mechanistic. The former group includes the crude Epicurean theory, the more complex Stoic account, and - though mechanistic is a strong word for it - the Aristotelian position as well. Plato is the sole member of the minority group, but he happens to be right. The basis on which these two groups are separated is their assertion or their denial of a medium of sensation. At this point a subdivision within the mechanistic group must be made. Aristotle and the Stoics, on the one hand, had assumed the existence of a continuous medium, while Democritus and the Epicureans had used the medium of a stream of effluxes passing from the object to the eye. The difference between Aristotle and Democritus runs deeper than the one problem of sensation: Their contrary theories are applications of more general world views; and likewise, when Plotinus rejects them both, it is because of his underlying principles. Without these basic postulates Plotinus' position would be extremely puzzling, for he denies both the continuous medium of Aristotle and the effluxes and void of Democritus.
Since Aristotle had argued that a medium was necessary because a sensible quality itself at a distance from the organ could not affect the organ, Plotinus had to supply some general view to explain what appears to be a case of transmission without a medium. To this end he offers his theory of sympathy.14 Because it is a perfectly general principle, comprehending all types of agent-patient relationships, it does not advance the study of sensation in particular; it does, however, harmonize the rejection of a void and the rejection at the same time of a medium.
Plotinus' high rank as a philosopher is at least partly grounded in his success at synthesizing elements from the many preceding schools of thought without becoming entangled in their systematic difficulties. The theory of sympathy is a happy illustration of this process. First, there is the Pre-Socratic principle that like acts upon like: The cause and the effect, whether in epistemology or in physics, must resemble each other. Second, the term itself is borrowed from the Stoics, who derived this notion from their theory of complete mixture. But the chief inspiration, as always, comes from Plato. The world, therefore, is conceived, not as an aggregate of inanimate atoms moving mechanically in a void, but as a living being, or as some translations crudely call it, an animal. In a living being it is not literal proximity that determines one organ to affect another. The eyes, for example, produce a sympathetic reaction in the stomach without affecting the more closely situated teeth. Similarly in the universe on object is an agent and another is its patient, not by any means of rigid connection, but by an action at a distance depending on resemblances between the two objects.
As the acceptance of the general theory of sympathy results from the falsity of mechanism, so the application of this theory to the particular case of sensation depends on its displacing the theory of a medium, and can be indicated by continuing the previous illustration. Suppose the teeth and the gullet were the means of transmitting an affection from the eyes to the stomach. Under such conditions the reaction of the stomach would be less by the amount of energy absorbed by the intervening parts. Hence a medium would dull one's perception. While admitting that air or some type of body occupies the space between the organ and the sensible object, and that this body is in contact with both, Plotinus denies that it is a means of vision. A dense body placed between the eye and the object obviously prevents vision; if the body is less dense vision will perhaps be possible; and the rarer the intervening body, the less of a hindrance to vision it will be; but no matter how rare, it cannot be considered a means or an aid to seeing.
Contrariwise, if a block of wood is put into the first, the fire can reach its center only by means of the parts nearer the surface, but, as long as these parts are not destroyed, they act as insulation. Now some natural processes do indeed require a medium. And the very reason that nature provides a medium in these cases is that thereby the affection may be modified to prevent destruction. If fire acted at a distance without a medium, human life would be impossible. But obviously sensation falls under a different category. Arguments will show that sensation, unlike combustion, is a case of action at a distance. And yet, without a medium, at least without an intervening body, there would be no sensation. The conception of the world as a living being implies a continuous universe. But continuity as such is not the explanation of sensation, since, if it were, everything would have a sensible perception of everything. A continuum is, however, an indispensable condition of sensation, and a void would make sensation impossible, not because of mechanical principles, but because a void would destroy the world as a single living being, rendering all action at a distance impossible.
The situation is similar to the fall of a stone. Though it must fall through the air, the air is not the medium of its falling; its fall is explained by its weight, not by the air pushing it downward. Tree grow upward through the air, but obviously air is not the means or medium of their upward growth. The basic difficulty with the notion of a medium is that it involves a mechanical explanation of sensation, and mechanism is a mistake. Therefore, in sensation one must set aside both a medium which transmits by being itself affected, as wood is means and insulation to fire, and also an unaffected medium through which alleged streams of sensible species pass as a stone fall through the air.15
Finally, Plotinus mentioned against that most important of considerations - the epistemological. If a sensible object affects the air, and then the affected air at least affects the organ, it follows that we do not see the object itself, but simply the air.
With the notion of sympathy as a background, the more specific explanation of sensation is derived from Plato. In the Timaeus Plato assumed that the eye shoots forth a ray of light; this ray fuses with the homogenous light of day; if then it strikes an object or a light reflected from an object, "the motions are transmitted through the whole body into the soul, and this is the sensation we call vision."
Plato's theory therefore seems to require a medium, the light of day. But Plotinus is in essential agreement. His arguments against a medium must be understood in their historical context. The prevailing materialism of the recent philosophers had required a physical medium for sight, and they had commonly identified that body as air. Both Epicureans and Stoics assigned an important role in the process of sensation to the air.16 Hence when Plotinus argues against the existence of a medium, he is not denying a function to light, but is attacking views of the mechanical production of vision by a physical medium such as air. Light itself, however, is an impassible or non-mechanical medium.
The one correction, or rather the one clarification, that the Platonic theory needs is the recognition that the external or foreign light of day is not indispensable to sight. While it is needed in order to see objects at a distance, one may with pressure on the eye-ball have a vision of the light within the eyes. This is a seeing that requires no light of day.17 Plotinus also notes that Plato's theory leaves unexplained our perception of the stars at night. Consequently it is the light which issues from the eye, not the external light of day, that is the chief cause of sight. This ray of light is a living organ, an extension of the soul, which stretch out like an antenna to touch the visible object. Vision, therefore, becomes similar to touch,18 and with this explanation of Plato's theory no medium is necessary.
Since the theory of sympathy was to account for action at a distance, the question immediately arises as to the necessity of function of the visual ray. The answer is found in the following lines.
In this case one must discover whether sight [the visual ray] must proceed there [to the object] because an interval exists or because there is a body in the interval. Now, if it is because of a body in the interval, there will be vision if the obstacle is removed. But if it is because of the interval simply, one would need to assume that the visible object was inert and completely inactive. But this is impossible.19
To examine the end of this quotation first, the last two sentences reflect the theory of sympathy by asserting the power of affection resident in any body or object. The only assumption by which one could say that the interval alone and not the corporeal intervenient was the cause of the visual ray would be the complete passivity of the sensible object. But sensible objects are not passive. Far from being inert, it is the activity of the sensible object on the organ that is the effect cause of sight. For touch, which is a clearer illustration, not only reports to us that an object is near, but by being affected it informs us of the objects qualities. These qualities are so active that even touch, unless there were some separating medium, would sense them at a distance. This actually occurs when standing before a fire. We are warmed before the intervening air is warmed, and to a higher degree than it. If, therefore, there is a power to act in the sensible object and any degree of receptivity in the organ, no medium of sensation need be assumed. At the same time, this consideration shows that distance alone does not explain the necessity of a visual ray.
The main point of the quotation is that a dense body, usually air, fills the space between the eye and the object; that this reduces the intensity of sympathetic action; and that it would prevent sensation altogether unless this insulation were pierced by the visual ray. Therefore, when Brehier20 asserts that this consideration assigns to the visual ray only an accidental reason for existence, his phraseology is plausible. If there were no obstacle, sight would occur without the ray. But with Plotinus' more general world view in mind, the reason for the ray's existence is seen to be a uniform and regular accident. For one must remember that the world as a living being is continuous and therefore some body will always occupy the interval. So, then, when Brehier also wrote, "de plus on ne voit pas pourquoi la faculte visuelle sort ainsi de l'oeil," he must have missed the point that the ray has as its function the piercing of the obstruction. The obstruction is the air, which is dark.21 When the obstruction is too tense, as it would be if a stone wall were between the eye and the object, the ray cannot penetrate it and vision of the object in question ceases.
The utilization of a visual ray to pierce obstructions may seem to a modern reader to be inconsistent with the spiritual, non-mechanical explanation of vision, but Plotinus was confronted with the stubborn empirical fact that we cannot see through opaque bodies and hoped that the assimilation of all bodies, air included, to soulstuff would acquit him of any serious charge.
To avoid possible misunderstandings and especially to support further the denial of a medium for perception, it is necessary at the risk of a slight digression to indicate the nature of light. Most emphatically light does not receive an affection and transmit it to the organ. Aside from previous arguments against transmission, light by its nature is incapable of progressive transmitting.
First, air is not the substratum of light.22 That light does not depend on, or is not an affection of, air is proved by the fact that light belongs to every fiery body and to some stones. But this fact of itself does not rule out air as necessary to the passage of light from its source to the eye or to an illumined object. Now if light were a quality in the Aristotelian sense of the word, its propagation would require a substratum as a medium. But light is not a quality, either of the air or even of the source. If light were an accident or passive state of anything, an object illumined by the Sun would retain the quality of brilliance after the Sun had set. And this, too, would involve the consequence that the Sun is constantly losing its light.
Nor is light a substance. It is, instead, an activity of something, and as such can pass through, or, better, can pass over, a distance even if the distance were a pure void.23 Air could be needed as a substratum only to prevent the ray of light from falling down, or to coax it from the luminous body and start it on its course, and both of these reasons are absurd.
An activity, on the other hand, comes from a substratum, but does not pass into another substratum. The other substratum, however, may be affected if properly placed. In this, life and light are analogous. Life is an activity of the soul that may animate a body properly situated; but, if no body is present, life is still an activity. Similarly light is the activity of a luminous body. The dark, dusty air does not produce light nor transmit it; it obscures it.
The main conclusion, therefore, is that air as a continuous medium is not necessary for the transmission of light. Nonetheless, body is required for the perception of light. Above the Earth's atmosphere, as we know today, one can see the sunlight only by looking toward the Sun - a body. On the Earth's surface, on the other hand, we can see the sunlight without turning toward the Sun because of the air, or the dust in the air - a body. If therefore the Sun itself is to be seen, it must be a body and cannot be pure incorporeal light. If it were pure light, there would be light in no other visible object, and only the Sun could be seen, for the other visible objects are not pure light.24
Plotinus also adds a much less convincing application of his principles to sound and audition.25 All sensation, then, is to be understood as an instance of sympathy without benefit of media.
Body and Soul
Proceeding inward from the external object through the visual ray, the exposition must next treat of the necessity of organs in sensation. When light is denied the title of physical medium between object and organ, when the force of sympathy seems to raise the possibility of action by the sensible object directly on the soul, it may appear than Plotinus' spiritualism has so extruded body from the situation that not even an organ is necessary. This, however, is not quite the case. For, though there is no medium between organ and object, the organ is itself a medium between object and soul.
A sensation is not an impression, and, as Plotinus frequently repeats, the soul is impassive. But "to deny that alterations take place and are sensed distinctly is contrary to clear fact. But while admitting this, one must ask what it is that changes. For if we attribute these modifications to the soul, we are in danger of regarding the soul as if it could blush or turn pale."26 "In the case of sight, the seeing is an activity and it is the eye which is passive."27
From these two passages it is clear both that the soul is impassive and that sensation is an activity. And again:
Sensations are not passive states, but activities with reference to passive states. They are judgments. Passions arise in something else, in a sort of body, but judgment occurs in the soul and is not a passive state. Otherwise there would be need for another judgment, and so on in an infinite regress. Nonetheless we have here a difficulty if the judgment as such has nothing of the thing judged. Or, if it has an impression, it has been modified. However, it is possible to say even of the so-called impressions that their mode is completely different from what is supposed. Like thought, they too may be activities and may be able to know without undergoing any modification. And in general neither reason nor volition subjects the soul to changes and alterations, such as the heating and cooling of bodies.28
These lines disclose the main reason for denying that sensations are passive states. Such states must be conceived as heatings and coolings, that is, as corporeal motions. Aristotle originally defined the category of passivity on the basis of physical changes, and the term should be restricted to that meaning. Sensation, then, is an activity. The word activity, however, regardless of its original significance, Plotinus uses precisely to avoid physical connotations. If modern readers find it difficult to see how anything can be active without changing, this very difficulty should make it easy to see that Plotinus is attempting to remove all notions of body and its peculiarities from the concept of soul. He is struggling with the concept of pure spirit. Sensation, then, is not a physical motion. To be sure, all this refers to sensation when the soul is regarded as the subject. It is that sensation which is called a kind of judgment.29
There is also the more literal, or at least the more physical, phase of sensation, in which the subject of study is not the soul as such, but the organ regarded as a mean between the object and this more internal consciousness. Hence Plotinus does not hesitate to call sensation, in this derivative or lower sense, a motion through the body.30 Soul and body collaborate in sensation; the former is the artisan, the latter the instrument; for which reasons sensation is called a work common to body and soul.31 Or, more fully, sensation is the soul's using the body for grasping sensible objects.32
Each part of the body illumined and animated by the soul participates in the soul in its own peculiar manner. And according to the fitness of the organ for its work, the soul gives it a power suited to that work. Thus the power in the eyes is that of sight.33
The organ is not of itself capable of producing a sensation; it is a means and must therefore be used. Plotinus' words are:
An organ is not sufficient for vision or for sensation of any kind. The soul must be inclined toward the sensible objects... And when we are engrosses in intellectual objects, sight and the other sensations escape our attention; and in general, if we attend to one thing, we miss the others.34
If the organ is not sufficient, however, is it even necessary for sensation? Why must the soul use an organ at all? A preliminary and very partial answer to this important question is that organs differentiate the several types of sensation. Were there no eyes or ears, sight and sounds would not be disparate sensations. The sensible object itself is an image of an ideal object; it differs from its model by being less unitary and more extended in space.35 In grasping the sensible object, therefore, we grasp the intelligible object after a fashion. Thus it may be said that all perceptions are perceptions of forms, though these forms may take on all shapes, such as red, sweet, or loud.36 This is a partial answer to the question why organs are necessary for sensation; at least is shows why organs are necessary for disparate sensations. But why should there be disparate sensations at all? Why cannot the soul perceive without any organ?
The most explicit answer to this question is given in IV, iv, 23. The chapter opens with a definition of sensation: "the perception of sensible objects is the grasping of qualities attaching to bodies by the soul, or by the living being, when it is conscious of them and makes a copy of them on itself." To grasp these sensible forms, the soul cannot be alone without an organ, for by itself it perceives its own content, and this is intellection, not sensation. If it is to perceive other things also, it must first have come into possession of them either by becoming like them or by being conjoined with something that is like them. To become like those things, so long as the soul remains by itself, is impossible. And hence the theory of sympathy does not provide for the action of a sensible object directly on the soul. The soul is not the man that the soul produces; even if it were able, when alone, to attend to a sensible object, there would be no useful purpose served, since, on the assumption that sensation is to lead us to the intelligible world, the soul alone can already contemplate this intelligible model. But, as a matter of fact, it is not able. The sensible object escapes the pure soul because, in reality, the soul does not have the means of grasping a sensible object. To illustrate: Take a visible object that the soul sees at a distance; granted that its primary purpose is to bring before the soul its ideal model in the intelligible world, and in this sense is related to the soul as an indivisible reality, nonetheless the actual process requires an extended, colored object, and the soul sees this extension and color.37 Therefore, these two, the soul and the external object, cannot be the only factors, since the soul is impassive. There must be a third and passive factor also to receive the sensible form. Sensation was previously explained to be a case of sympathy. Now this third factor is precisely the organ that can experience a sympathetic reaction to the sensible object. The organ must come to possess the same modifications that are in the object and be of one matter with it. One is tempted to repeat Aristotle and say that the eye becomes red and the ear sonorous. Thus the organ will be passive, the soul will know, and the passive state will be such as to preserve something of the body producing the affection without, however, being that body.
Just as the visual ray is a sort of extension of our soul, a semi-soul as it were, so too the sensible quality and the sensible object are derivatives of the world-soul on a lower level of reality than our soul or the visual ray. Because, then, all these factors are basically spiritual in nature, the organ, like a mean between the object and the soul, has an affection lying between the sensible and the intelligible like a mean proportional. Thus in a fashion it joins the extremes to each other, being both receptive and annunciatory, make for the purpose of being like both. Since it is an organ - that is, an instrument for acquiring a certain kind of knowledge - it cannot be identical with the knower or the known, but is adapted to be like both, like the external object by reason of passivity, and like the internal soul because its affection becomes a form.
Perhaps in this last clause one suspects that the whole unsolved problem is smuggled back into the alleged explanation. Materialistically minded people have no trouble imagining a sensible object's impressing an organ. Whether it be by sympathy or by propagated light rays makes little difference. But how can the soul perceive the affection in the organ? How does a chemical change in the retina become an intelligible form? And if the soul perceives a chemical change in the retina, what becomes of the realistic epistemology that asserts we grasp things and not mere phenomena?
It is quite clear that Plotinus intends to maintain his realist or dogmatic position. Although it may seem at first that the soul perceives the affection in the organ and not the object, Plotinus continues to assert that the organ must be different from the object perceived.38 In the immediate context the proof of this assertion reduced to the problem why an organ is necessary; and if the argument of the chapter has demonstrated this necessity, the problem is solved, for to use an organ is to have sensation.
Perhaps this does not yet seem to be an altogether satisfactory escape. To Plotinus, however, it serves to advance the solution more than the materialist would be willing to admit. Materialism may have no trouble with chemical changes on the retina (except the troubles of life), but, as Plotinus showed in one of his earliest tractates, materialism is notoriously incapable of advancing beyond unconscious chemistry. The objections suggested arise from trying to judge Plotinus on a materialistic basis. Plotinus, however, convinced of the failure of mechanical explanations of life, has already attacked the problem from the other end; for him, it is the problem of explaining organic functions in terms of soul rather than of explaining sensation in terms of chemistry. Neither the red in the eye nor even the read in the object is a mere matter of chemistry. In this spiritualistic system the red of the object is the result of a spiritual contemplation,39 and the perplexity is removed because the sharp Cartesian dualism that produces it is not present.
And yet Plotinus is not completely satisfied. To give a complete answer, it is necessary to exhaust the relation between soul and body. The fundamental importance of this investigation is seen, aside from the logical exigencies of the system, in the fact the Plotinus devoted one of his last, his most mature, and most complicated tractates to this subject.40
The tractate opens with the question whether pain, pleasure, sensation, etc., have their seat in the soul so as to involve a motion of the soul, or in the body, or in a resultant combination. From the impassivity of the soul Plotinus deduces that these experiences cannot have their seat in the soul. Sensation is explicitly denied to the soul on the ground that it is a reception of the form or affection of a body.41
Even though the soul uses the body as an organ, it is no more compelled to receive the affections that come through the body than carpenters are compelled to receive the passive states of their tools. But must not the soul have sensation if it is to use an organ and know42 the external affections by sensation, for the use eyes is to see, to use an organ is to sense? How, then, to return to that most difficult question, do the affections of an organ come before the soul? A body may share its states with another body, but how can a body transmit a bodily affection to the soul? This would be the equivalent of one object's suffering the modification of another. As long as one is the user and the other is the thing used, each must be kept distinct; and he who makes the soul the agent separates them. The solution involves a distinction. The soul itself is two-fold, one part being the agent strictly, and the other, that nature which is the result of the soul's illumining or animating the body, being itself a sort of organ.
Comparative philosophy as well as the wording of this solution seems to suggest that Plotinus, to connect two unconnectable elements, resorted to a device popularized by Philo and used with abandon by the Gnostics. It is the device of mediators. If God is so transcendent or holy as to be unable to come into contact with matter, and yet must do so for this or that reason, a mediator, neither God nor man, is invented to bridge the gap. Athanasius, in his Defense of the Nicene Definition, makes the point that such an expedient renders impossible the creation of or contact with a first mediator, and so an infinite series results.43 Late antiquity, as the multiplication of ranks in Proclus shows, went its way inventing mediators; are we not to say that Plotinus himself was already well advanced on the same road? The disparity between organ and object is halved by the visual ray; the disparity between organ and soul is halved by this nature; and so one is to leap across the Grand Canyon by jumping half the distance first.
Utility and Knowledge
The purpose of sensation met with so frequently as to raise a doubt whether there be any other is utility. There is a common contrast between utility and knowledge, and sensation may seem to be restricted to warning the soul of corporeal agents injurious, or advantageous, to the living body. "When the intellectual intuition and knowledge of objects is very clear, it is not necessary, even though these objects occur sensibly, to disregard that knowledge and fix the attention upon the particular sensible object, unless one has to manage it for some task."44
Since pleasure, pain, and desire are classified as sensation, what is said of them may with care be transferred to sight and hearing. In IV, iv, 18ff. Plotinus argues that, although the true person is the soul which animates the body, and not the body nor even the animate composite, we are not free from the body; it belongs to us and we must care for it. Therefore pleasures and pain concern us in proportion as we are weak and dependent on the body. Pain is then defined as the recognition of constraint when the body is deprived of the animating images of the soul; and pleasure is the living being's knowledge that the image of the soul is again being harmonized in the body with resulting health and wellbeing. While pleasure and pain themselves belong to the body, the perception of the pleasure or pain is in the soul, or more exactly, in the nature. The distinction between pain and the knowledge of pain provides for localizing the affection. If the soul itself felt the affection, the pain would be wherever the soul was, and not merely in the finger. And further, if the soul itself suffered, it would be incapacitated for an accurate reading of the trouble in the body.
The explanation of this lies in the fact that there has come into existence a body that wishes to be more than a body and has acquired motions the soul does not have. Thus for its preservation and development it is forced to turn to sweet, bitter, and many other objects, of which it would have no need were it body only. By taking note of pain, the soul, which wises to deliver the body from harm, engineers a flight from the harmful object. And this flight is first seem in the contraction of the organ primarily affected, as when the finger jerks away from fire. Hence an important function of sensation is the preservation of body.
We must now discuss whether sensation is for utility only. If the soul when alone has no sensation, but senses with the body, sensation must be for the sake of45 the body. Sensations come from the body and are given to the soul by reason of its union with the body, or in fact they follow of necessity [from that union.]46 For the greater the bodily modification is, the more forcibly it arrives at the soul; and sensation is so ordered that we are protected before the agent becomes so great as to cause injury, or even before it comes near. If this is the case, sensations are for utility. For, even though they also aid knowledge, they do so only for one who has no knowledge and is ignorant through misfortune, so that he may recollect what he has forgotten. Sensations would be of no use to one who had no need or who had not forgotten.47
That sensations are for preserving the body from harm is thus sufficiently clear; but who on Earth, according to the Platonic theory of reminiscence, is not forgetful and does not need to recollect? From this paragraph on utility, therefore, one is led directly to the problem of sensation's function in learning. Anything resembling an exhaustive account of Neoplatonic epistemology is obviously out of the question in the remaining pages of this article, but something to the point of the problem as stated is called for.
First of all, in the section on emphasizing utility, there is a sentence which, despite its hesitant context, points beyond utility. "For in sensation there is also, beyond utility, a sort of knowledge that is not without refinement, such as knowledge of the Sun, the other planets, the heaven and the Earth. For the sensation of these objects is a pleasure in itself."48 Whether this refers to the aesthetic response, or to astronomy, or both, it is at any rate beyond utility and within at least the wider sphere of knowledge.
Other preliminary references include the assertion that the belief that sensible objects exist depends on sensation.49 And later in the same tractate discussing the classification of qualities, the suggestion is made that the difference among organs be used as the basis. And under the heading Body and Soul above, two passages were mentioned teaching that organs and not objects are the source of disparate sensations.50 Then, if classification is a matter of logic and knowledge, sensation has again gone beyond utility. Another preliminary text states that experience of evil in this world, and this must surely include sensation, produces by contrast a clearer knowledge of the good.51
Much more explicit, however, is the argument connecting sensation with memory and imagination. In general, sensation produces contents for memory,52 the visual image of sensation becomes, when sensation no longer exists, a memory-image, and thus sensation culminates in, what is the equivalent of memory, imagination. Thus a progress toward knowledge has been started. Sensation is a critical faculty, and imagination is quasi-intellectual.53
To show that this is truly a progress toward knowledge, it is necessary to connect these images with the higher functions of discursion and intellection.
We separated the functions common to soul and body from those which are peculiar by the fact that the former are corporeal and not without body, but all those which do not need body for their actualization are peculiar to the soul; and discursive reason passing judgments upon sense-impressions already contemplates forms and contemplates them as it were with sensation. We mean discursive reason strictly, in the true soul. For true discursion is an activity of intellection, and often it is the likeness and union of external objects with internal objects.54
The connection between sensation and the higher functions, so obviously asserted in this quotation, is further established in the discussion of the Hypostases Which Know.55 It is not only sensation that deals with external objects; discursion and opinion also grasp them. Whether the intellect does so, is not so clear.56
The reasoning function of the soul, on the basis of images derived from sensation, combines, divides, and pronounces judgment. In the case of representations coming from the intellect, it observes them as if they were impressions, and has the same power with respect to these also. And understanding is gained as the soul recognizes and harmonizes the new and recently arrived impressions with those inherent in it of old. And this is what is meant by the soul's reminiscence.57
Plotinus is obviously referring to Platonic reminiscence, and since "the new and recently arrived impressions" must be sensible impressions, there is here, more explicitly than in the writings of Plato himself, a continuity between sensation and the higher knowledge. After asserting again, at the end of this chapter, that discursive reason is a meeting point for the impressions of sense from below and the "impressions" of intellect from above, Plotinus immediately attempts a more detail description of the connection.
For sensation sees a man and transmits the image to the discursive reason. And what does reason say? It will say nothing yet, but knows only and stands still; unless indeed it asks itself, "Who is this?" - if it has met the man previously - and says, by making use of memory, that he is Socrates. But if it should explain, it separates the material imagination gave it. If it should explain whether he is a good man, it would speak out of the things it learned by sensation, but what is said about them would depend on itself because it has a standard of good within itself.58
Not only are discursion and sensation so closely connected, but in the immediately following lines even the intellect is involved, for it illumines the discursive faculty to strengthen it for the sensation of good objects. In this way, therefore, a strict continuity is established from sensation through memory and imagination on to discursion and at least even to intellect.
Finally, there remains a slightly different question, whose answer, because it turns aside a difficulty, enforces this continuity from sensation to intellection. If intellect supplies us with the norms by which we judge sensible objects, how is it that we are not conscious of its action? Its activity permeates all our mental life, for there is no such thing as a bare sensation. Some element of judgment always enters, and therefore apparently we ought to be more continuously conscious of intellect than of sensation and discursion. In fact, since intellect never ceases to function, why are we not always conscious of its action?
One part of the intricate answer to this question requires a distinction between, to use later terminology, the noumenal self and the empirical self. The continuous activity of intellect is known to the noumenal self because intellect is that self. Plotinus draws a far-reaching analogy between our (the empirical self's) being unconscious of the activity of intellect and our being unconscious of many biological processes acting continuously in our body.59 If the vegetative life were the noumenal self, we, the empirical self, would be conscious of its functioning only under particular circumstances. And if this occasions no surprise, neither should our intermittent perception of the intellect's activity.
More explicitly, intellection escapes our notices because it does not relate to a sensible object; and consciousness requires sensible objects.60 Intellect and even soul, in its highest phases at any rate, have an activity prior to sensation and all perception. Otherwise to think and to be would not be the same.
The perception of these activities seems to occur when the thought is bent back, as if it had gone forth, had struck a mirror, and had returned. If the mirror is not there, or if its surface is damaged, there will be no image; but this does not affect the subject that would have been reflected. The soul, at least in its lower phase, is like a mirror. When in condition, it reflects the objects that would have been reflected. The soul, at least in its lower phase, is like a mirror. When in condition, it reflects the objects of discursion and intellection; thus we see these objects sensibly as well as know them with the prior form of knowledge. If, however, the soul is disturbed, because of bodily disorder, there is imageless, unconscious thought. Unconscious activity should be considered neither strange nor inferior. A courage, for example, that is too conscious is hardly noble; and a person reading with complete concentration on the subject-matter will be unconscious that he is reading. In fact, consciousness, as the opposite of concentration, weakens the acts it accompanies and dissipates their force.
Another passage of similar import considers the relation to sensation of discursion only.61 The immediate problem is the possibility of remembering concepts or reasonings. Since in the visual or auditory sense of the word there can be no "image" of discursion, Plotinus brilliantly suggests the verbal formula as a substitute.
For the concept is indivisible, and not yet externalized; it remains internal and escapes our notice. But speech, by unfolding it and leading it from the state of a thought exhibits the thought as in a mirror, and thus we have the perception of it, its conservation, and memory. And therefore, since the soul is always thinking, we have perception whenever it arrives at this stage. For thinking is one thing, but perception of the thinking is another; and while we always think, we do not always perceive. This is because the recipient not only receives thoughts from above, but also sensations from below.62
Even when Plotinus warns that, if the sensible world gain the mastery over the soul that has descended into it (the empirical self), it will be impossible to perceive the intelligible objects themselves, he confirms the view that only in sensation do we have the perception of thought. "For the intelligible object comes to us only when the soul has descended to the level of sensation."63 It cannot be said without qualification that an event in any given part of the soul will be perceived. If the event permeates the whole soul, no doubt we shall be conscious of it. But even with respect to the lower functions, such as desire, there is no consciousness if it remains in the appetitive faculty. To be perceived, it must pass on to the inner faculty of sensation, or discursive reason, or both. And if this be true of the lower functions, why should it not be true of the highest functions?64
In other passages Plotinus speaks of setting aside the body, the soul that fashions the body, sensation, desires, and the other faculties that incline us toward perishable things, in order to know intellect.65 And also, in apparent contradiction to the previous statements that we always think but do not always perceive, we have the assertion that we always sense and reason, but do not always use the intellect.66 The apparent inconsistency is removed by observing the much more accurate definition of self in this passage. Previously it was the whole soul that was discussed, and the stage at which perception occurred had to be distinguished from the other phases of soul. Here there is mainly in view the empirical self, and man is identified with the discursive faculty itself.67
The exhortation, therefore, to leave the realm of sensation is in no sense a retraction of the theory of sensation, but a confirmation of it. Sensation is related to knowledge by being a first step toward knowledge. Had there been no incarnate life, sensation would have been unnecessary. Under the actual conditions most men must begin with sensation. "If anyone cannot grasp the first and purest contemplation, let him take the faculty of opinion and ascend from there. But if he cannot even grasp this, let him take sensation which provides us with forms more extended in space..."68
This in fact is the notion that unifies the whole theory. Sensation can initiate knowledge for the express reason that sensible objects are extended in space. They are the visual, or sensible, images of eternal realities. In literal sensation, therefore, we are actually in touch with reality; to be sure we do not have a very firm grasp on it, but at least it is a contact.
The long passage, therefore, sublimating sensation is well summed up in its concluding words, which are also the appropriate concluding words here.
It is clear and the argument has demonstrated that heavenly realities do not look upon things here below, but objects here below depend upon and are imitations of the objects there. And man here holds from Man those powers which have reference to the intelligible objects. Sensible objects are thus united with the sensible man, and intelligible objects with the intelligible Man. For these heavenly sensibles, as we may call them, must be grasped in another manner because they are incorporeal; sensation here, because it deals with bodies, is more obscure than apprehension there - which we also call sensation - although it seems clearer.69 And therefore man here is a being of sense because his perception is weaker and what he grasps are weak images of objects there. Consequently sensations here are obscure intellections, and intellections there are clear sensations.70
1. From The Philosophical Review, July, 1942.
2. Zeller, Die Philosophie der Griechen, III, a, 3te Aufl., S. 580.
3. L'idee de verite dans la philosophie de Saint Augustin 171: "Four Plotin l'ame sent parcequ'elle se saisit creant l'objet sensible."
4. VI, vi.
5. V, iii, 1, 20; V, iii, 2, 3.
6. This consideration is expanded in IV, v, 3, 26ff.
7. V, iii, 5, 17-28 and context.
8. Op. cit., III, 2, 3te Aufl., S. 582.
9. I, i, 7, 9-12.
10. V, v, 1, 15-19.
11. I, i, 7, 1-6.
12. IV, vi, 3, 16-19.
13. V, iv, 2, 46.
14. IV, v, 1, 35.
15. IV, v, 3-17.
16. Lucretius, De Rerum Natura, IV, 244-255; Arnim, S. V. F. II, 864, 866, 868. Compare Theophrastus, De Sens. 51.
17. V, v, 7, 24ff.
18. IV, v, 4, 10ff. Brehier, Notice (in loc.) page 61, understands the reference to touch as a reductio ad absurdem, and, because he can see no function for the visual ray, seems to conclude that it does not exist. That Plotinus asserted the existence of such a ray is evident from V, v, 7, 27, and IV, v, 7, 23-25. Brehier's interpretation requires the argument to be construed as a modus tollens, but since the conclusion Plotinus intended is patently the rejection of a medium, no such construction can result in a valid syllogism.
19. IV, v, 4, 17-22.
20. Notice, page 61.
21. Compare IV, v, 2, 15ff., and 56-61. Mackenna is clearly wrong if he identifies the body in the interval as the visible object itself. His translation of IV, v, 4, 20, as "If by the presence of such a body, then there will be vision though there be no intervenient," ruins the progress of the argument.
22. IV, v, 6.
23. Contrary to Aristotle, De Anima, 419a15.
24. V, v, 7, 8-16. The last part of the argument limps even after confounding visible with light.
25. IV, v, 5.
26. III, vi, 3, 4-9.
27. III, iii, 2, 53.
28. III, vi, 1, 1-14.
29. I, i, 6, 11.
30. I, i, 6, 11.
31. IV, iii, 26, 1-9.
32. IV, vii, 8, 2.
33. IV, iii, 23, 1-6.
34. IV, iv, 25, 1 and 5. Compare IV, vi, 3, 16-19.
35. V, iii, 9, 30-32.
36. IV, iii, 3, 12-20.
37. This sentence is the interpretation of the difficult lines IV, iv, 23, 15-19.
38. IV, iv, 24; and the first section of this article.
39. III, viii.
40. I, i.
41. Mackenna translates I, i, 2, 26-27, as "sensation is a receiving - whether or an Ideal-Form or of an impassive body." This virtually impossible interpretation depends on the rejection of an emendation by Gollwitzer, who substituted η χαι παθους for η απαθους. Gollwitzer might have better omitted the χαι, for it is not a disjunction but an explanation that is intended. To prevent the mistake Mackenna made in taking εδους, a Ideal-Form, Plotinus added η παθους. That εδους does not invariably mean Ideal-Form is clear from lines 3-5 of this same chapter. H. F. Muller in Plotinische Studien III, Hermes LI (January 1916) 110-111, rejects the emendation and anticipates Mackenna's interpretation. He does so only by utilizing the distinction made later between sensation of the soul and sensation by the animate body or nature. But if Plotinus had intended this internal, higher sensation, the conclusion at this point would have been that the soul indeed is the seat of sensation. Since the conclusion here is exactly the opposite, Plotinus must have meant the organic phase of sensation.
42. Brehier's emendation in I, i, 3, 7, does not seem to be a happy one. Either Ciz. or A B D is better.
43. The Christian mediator, who is both God and man, involves, of course, a different notion of transcendence, springs from problems foreign to paganism, and does not face this objection.
44. IV, iv, 8, 3-6.
45. Δια here probably means "for the sake of"; Mackenna's "by means of," while plausible, involves considerable tautology and does not follow through the notion of utility.
46. There is a textual difficulty here. The reason of B, επαχολουθουσα gives an explanation or slight modification of δοθεισα. The γαϱ clause following explains why sensations necessarily follow the union of soul and body. The reading επαχολουθουσης, adopted by Brehier, is beset with grammatical difficulty. Presumably it would mean that the soul is compelled to follow. This notion, however, neither connects so smoothly with the preceding, nor is it so well explained by the following.
47. IV, iv, 24, 1-12.
48. IV, iv, 22, 40-43.
49. VI, iii, 10, 12-17.
50. V, iii, 9, 30-32 and IV, iii, 3, 12-20.
51. IV, viii, 7, 15.
52. IV, viii, 29, 19ff.
53. IV, iii, 23, 31.
54. I, i, 9, 15-23.
55. V, iii, 1ff.
56. V, iii, 1, 20. Διανοια and δοξα grasp external objects in a sense pertinent to the present subject; νους may do so in a fashion further removed from the literal meaning of sensation. And if this be the case, sensation will be an aid not only to discursive reason, but to νους as well.
57. V, iii, 2, 7-14.
58. V, iii, 3, 1-9.
59. I, iv, 9, 24ff.
60. I, iv, 10, 2. Brehier says that sensation is the only means of becoming conscious of intellectual objects. Plotinus says as much elsewhere. Mackenna says action on sensitive objects must proceed through the sensitive faculty. Certainly refers to . Apparently Brehier has given a better reason than Plotinus.
61. IV, iii, 30.
62. IV, iii, 30, 7-16. The last two sentences, if disjoined from the context, might give the impression that sensation hinders the perception of thought. But the first part of the quotation shows how these infelicitous lines must be taken.
63. IV, viii, 8, 6.
64. The same considerations are repeated in V, i, 12.
65. IV, iii, 9; V v 6.
66. V, iii, 3, 28 and 39-41.
67. V, iii, 3, 35.
68. V, iii, 9, 28-31.
69. In the Greek of this sentence Plotinus did not achieve the clarity of his heavenly vision.
70. VI, vii, 7, 19-31.
