What Do We Know?

The table on which I am writing has a blond color to its grain with occasional stripes of dark grain running through it. To my touch it feels hard, and it has a permanence about it that has made it endure about fifteen years of hard wear. I know the table well since my wife designed it and we built it together. The table can be experienced by anyone who walks into my study. But according to modern physics the table is composed of empty space. Instead of a solid piece of wood, physicists would speak of atomic particles whipping through this empty space called a table. This view of the table casts doubt on its solidarity, its color and permanence. Obviously, this table of the physicists is not seen by the naked eye. Which is the real table? Are there two tables? Is this just two ways of talking about the same thing?1

Another example relates to our experience of light. When I look at the sun rising in the glory of the morning, what do I see? If the sun is 93 million miles from my vision, then it has taken about eight minutes for the light I experience to come to me. When I say I see the sun, the actual sun has moved in its earthly viewing position to a different position. Thus at evening the sun has already set before I see the last direct light from it. This puts me in the unusual position of saying I see the setting sun when it has already set. The example can be more complicated in talking about stars. Some stars are said to be so far away that it takes light thousands of years to come to our vision. When light is seen by me on a dark night, can I say that I see the past? Note how paradoxical it sounds to say that I see a star that may no longer actually exist!

If we switch from the far way to the present at hand, am I really seeing the table on which I write since there is an infinitesimal gap between the light striking the table and the light being picked up by my eye?

What can we really know about the world about us? Do we really see it? Are we trapped within our mind and all that we ever "see" are images of the outside world? Does the knowing situation remove us so completely from the outside world that we can never know what it is like?

Some of these judgements are made about certain theories proposed to explain what we really know about the world. We must turn now to look at the various proposals.

A. Common Sense Realism (naive realism)

Common sense realism is supposed to refer to the way that the man on the street, or the common man, understands the "knowing situation." Who is this man on the street? He has never written his philosophy and so we cannot read a defense of his view. This is interesting for two reasons: (l) "anyone intelligent enough to write about the problems of perception is intelligent enough not to commit the errors ascribed to that position,"2 and (2) that position is frequently criticized in an unfair way. To see this, look at a summary of the position and the criticisms leveled against it.

Common sense realism means: (l) that we experience objects directly. When I touch the door, or see the door, I am really touching or seeing the door, not a carbon copy or sense data image of it. (2) When I experience an object, I am perceiving it independently of myself; it is not just an image in my mind, and (3) when I experience an object, i.e., a door, it possesses the qualities which it appears to me to have.

If this may be regarded as a fair summary of common sense realism, let us note the criticisms against it. The criticisms compose a general attack upon the reliability of the senses and the tacit conclusion is that since they cannot be trusted in certain illustrations, then they are generally unreliable. A few examples will serve to illustrate. Vision is indicted first. When an oar is thrust into the water it appears bent although we have just seen it as straight. Which is the true vision--the oar in or out of the water? A coin on a desk is circular, but when you look at it from a distance, it looks elliptical which is contrary to the nature of the coin. What we see from one angle contradicts what we see from a different angle, hence the conclusion--the senses are unreliable. Similarly, the railroad tracks are known to be parallel, but in the distance
they appear to come together. The mirage on the highway is something that everyone can see in the car, but vanishes when you come to that point. Standing by a 747 before take-off one is swamped by the feeling of its size, but as it lifts off and climbs to a thousand feet or so, it seems quite smaller Are we seeing the jet as it really is?

Second, the sense of touch is illustrated as unreliable by a common experience of putting a cold right hand into water and a warm left hand into the same water. The water will appear warm to the right and cool to the left hand. Which statement can I trust about the water? When a man loses an arm, he experiences a sensation seemingly located in the missing limb. In the third sense, sound, common sense realism appears to come off no better in the criticisms. At a track meet one seated at the far end of the stadium will see the runners start before hearing the firing of the gun, but the rules of the game and reason indicate that this cannot be so. Thus the hearing is deceived. The other senses, smell and taste, are also regarded as unreliable since a cold can diminish both in their ability and sensitivity. There is no need to multiply illustrations. The general conclusion about common sense realism is that the senses are unreliable.

As if this were not enough, we must say a word about the unusual, i.e., hallucinations, dreams, and illusions. Do we really see things in these experiences? A classic example is that of MacBeth and his hallucination of a dagger. One may say he "saw" a dagger but no one else saw the same dagger, for there was none to see. An elderly man suffering from hardening of the arteries may wake up in the night calling to his brothers to come help him move some boxes. To him the brothers are near and the boxes are "seen." But to an attendant the brothers are dead and the boxes are non-existent. What about the reliability of the senses again? Can we say that everything we see is there?

Are the criticisms above really destructive for common sense realism? There are philosophers who believe that they are.3 But something can be said in defense of common sense realism and in evaluation of the criticisms of the position. (l) One gets the impression that they are overworked by philosophers in an effort to make their own position look good. The use of these illustrations and the conclusions reached are questionable in many cases. Look at the illustrations of the water and hot and cold hands. Why a philosopher would conclude that the senses are unreliable on that basis appears prejudicial. The sense of touch stands up in reporting that the water is warmer to a cold hand, and is cool to a warm hand. This illustration really shows the versatility of the senses for reporting diverse situations. What would be a sense error is this: if our senses reported the reverse, colder to the cold hand, warmer to the warm hand. This would be in contradiction to what we know to be the case.

(2) The perceiving man is a total being and his senses may appear to contradict each other, but out of this seeming contradiction he gains more reliable sense knowledge. Take the example of the field event. The gun goes off seemingly after the runners had started, but the distance of the viewer and the runner is measured in experience by sight and sound together. As the runners come closer they appear larger--than when they started--and depth of perception is only gained by saying that we see things from this vantage point. Without the seeming contradictory report of our two senses in this illustration, we would have been led astray. The jet that takes off appears huge as we stand by its side before take-off, but after it has lifted off it appears vastly smaller. After lift-off, the jet is seen as an object in flight away from us, not as an object at rest. In both cases our vision is giving a correct report of the jet. We are not really seeing the same things in the two different illustrations. Without the perspective of depth and distance, which vision reports to us, we would be more readily deceived by this sense.

(3) The normal functioning of the senses must be presupposed. A color-blind man is hardly in a position to talk about colors. So likewise, a monotone in the field of music. The elderly man suffering from hardening of the arteries is obviously seeing something that is not there, but this is overlooked because of his abnormality. It may be that MacBeth's dagger would fit into this category also. But grant for the moment that the senses are sometimes deceived, no one maintains that man is an infallible interpreter of the nature of the world about him. To say that our senses mislead us in some of these examples is merely to say that we are occasionally mislead, and by means of the senses we come to find out which experiences are misleading. To conclude that the senses are entirely unreliable is not only unwarranted, but proves too much for any other alternate view.

(4) Another problem with the criticisms is that they generalize too much. Either the senses are absolutely right, or they cannot be trusted at all. A common sense view would say that most of the time I see things as they are when I say I "see" it, but sometimes I am mislead. Even in this I may be corrected by my senses. In a dense fog I think I see a man prowling around the house. Upon investigation I discover that there are no tracks and it was not a man at all. I did see something which upon reflection may be understood as an opening in the fog which had a darkened shape like a man.

(5) Some criticisms of common sense realism could be avoided if an adequate interpretation were given for the perception. I see the same jet on the ground and after lift-off. My description cannot be the same for both experiences--I see the jet. The jet ascending must be described in terms of its distance and speed into the depth of space. If we are inclined to look up and say, "I see the jet," which we do, then a defense of the senses, where called for, must lead us to be precise and say, "I see a jet ascending in the distance," and this is understood tacitly as a contrast to the jet we see parked on the ground. But where philosophy and accuracy are not an issue, "I see a jet" will be sufficient for anyone in both cases. An often used example centers around the star Sirius. The star may not exist, but as I look at it I see it. Thus I may be said to be looking at something that does not exist. Hence a contradiction of the senses. But if I stand out and look at the sky, I am seeing something. This "something" is a ray of light that started from Sirius a long time ago and is just now arriving in the field of my vision. I cannot conclude whether Sirius exists now or not. I can say that I see the light from a star we call Sirius.

Interpretations of experiences are frequently inadequately expressed. The familiar stick in the water appears differently than the stick out of the water. It is not just a stick in the water, but an experience of the refraction of light with a stick-in-water.

(6) If we cannot maintain that we see directly, then to interpose an image or sense data as an intermediate removes one a step further from reality. We are then in the uncomfortable situation of wondering if there is a reality beyond the sense data, or (convinced there is) wondering whether our sense images really correspond with the reality there.

(7) The problems of dreams and hallucinations are different. Both of these are unusual. Although a dream has a vivid appearance, upon waking we make a distinct difference between the dream and reality. The same holds for the hallucination. The victim of a hallucination knows this when recovery comes. In a dream we see something directly that may not exist in reality either for us or at all, i.e., if I dream that a bevy of beautiful girls is chasing me, upon awaking I may regret that it has no reality for me, although in my dream I saw the beautiful girls. Or, I may dream that I am being chased by that unusual creature of The Hobbit series, the orc, and although I see it in my dream I see something that doesn't have material existence. What shall we do? We can accept the courage of our convictions and say that dreams are seen directly and conclude perhaps they are real. This is hardly a warranted conclusion. On the other hand, we can say that man is not an infallible creature and that dreams, illusions, and hallucinations are a special problem peripheral to man's direct seeing. Thus one may say that MacBeth thought he was seeing something whereas he was not seeing anything at all. My dreams may be a product of memory, phantasy, or heartburn, but they are a production of my mind in some sense. While this conclusion may seem to hedge for common sense realism, it admits that not everything is known about either perception or dreams. Looking at other options such as regarding a dream or hallucination as an internal sense-datum, it becomes easy to conclude that all sense-data are internal and the problem of talking about the outside world is more difficult.

In conclusion, common sense realism is not the most difficult doctrine to hold in explaining the knowing situation. It regards that objects are objective and perceived directly but admits that interpretations are subjective and need critical evaluation. At the same time it must be admitted that viewing an object from one point is not a complete way of viewing things.

B. Representational Realism

Representational realism (or epistemological dualism) is a position advancing beyond common sense realism by virtue of a different theory of perception. The problem of relativism of the senses coupled with the difficulty of explaining error brought a search for a better theory. The father of the movement was Descartes, but the expounder of the theory of perception was John Locke (1632-1704). The central tenet of the view is that one does not know an object directly, but indirectly, or by the object being represented by something else to the mind. The image that strikes back of the eye is what is regarded as the representation to the knowing subject. This is carried along the appropriate nerve connections to the brain. The brain then interprets the message and concludes: "apple."

Representational realism or, the more current term, casual realism,4 has three important elements in it: (l) an analysis of the mechanics of perception, (2) the centrality of the sense datum or image, and (3) a good measure of skepticism about the world and its interpretation. We can look at these ideas in turn. The first, the analysis of perception, relates to the way we know. For Locke, the mind is blank at birth and experience furnishes it with sensations on which it reflects. When reflection on the sensations is finished the result is an idea. These reflected-on-sensations are, secondly, all that we can know directly. Thus these assume a central role in the theory. What is the cause of the sensations? The answer is found in the world beyond the sensations. The world is inferred from the sensations and is mediated by means of the sensations to the perceiver. If sensations are all that we know, then they not only become all important, but also raise the questions about reliability again. This leads to the third element in the theory, the interpretation of the sense data.

Locke, the father of the movement, attempted to understand how we know things. He divided up the information about objects into two qualities: primary and secondary. The primary qualities relate to shape, size, movement, solidarity, or those qualities that could be known by more than one sense. The secondary qualities of an object are those of a subjective nature, color, taste, smell, etc. The difference may be seen in looking at a cherry. We could measure the size of the cherry, and weight could also be measured. On both of these measurements we could reach unity of opinion about it. Because they are primary qualities they do not change from person to person.

The secondary qualities are not that rigid. How does the cherry taste? To me it is sweet and to you it may be sour. Is the cherry red? To my vision it may be deep red and to another it may come off a lighter red, but in either case we cannot compare our experiences to know if we see the same thing. Who is right? We cannot know. Now comes a difficult part of the view--the redness or lack of it, and the sourness or lack of it are not in the cherry, but in you and me. This is how variations in opinions are explained because taste is an intrinsically personal experience. What is the cause of the redness then? The redness is caused by the apple but it is not in the apple. When one is not experiencing the secondary qualities, they do not exist. (This is the jumping off place for the next view succeeding Locke, that of idealism and George Berkeley.)

This view leaves us with a measure of uncertainty or skepticism about the world. It is seen in two ways: (l) the datum or image in the mind that we experience removes us one step further from the real world, and we never know if the datum and the real world correspond, and (2) much of what we see in the world involves color, taste, sound, etc., and thus a subjective analysis of much of the world is all that we have.

In looking at the causal or representative theory, a number of factors are in its favor. Remember that the theory arose to solve the twin problems of error and illusion which presumably the common sense position could not. The causal theory offers a simple explanation for illusions, hallucinations and dreams. They are really ideas or images in our mind. They do not reflect the outside world. Similarly, error can be explained in that the image of the mind does not correspond to the real world, or, there is an image and no object to which it corresponds. Using the mirage, a public response from many people would show that it exists in the mind, but not in the real world. Even a rainbow can be seen by the public at large, but it cannot be touched, tasted, heard, or smelled since it relates to secondary qualities.

Is the position an improvement over common-sense? If it is, there are certain serious problems with the position. First, it is argued that although "the perceived qualities of physical objects are causally dependent upon the state of the percipient, it does not follow that the object does not really have them."5 It seems foolish to argue also that secondary qualities do not exist when no one is perceiving them. An apple does not alternately turn red and "blah" depending on the presence of an auditor. Second, if the secondary qualities are divested from an object not much is left and it is arguable whether along with giving up objective perceptible color one must also give up objective perceptible figure and extension. This point can be seen in Berkeley's criticism who argued that the same arguments used to turn the secondary qualities into the subjective sphere are also applicable to the primary qualities and hence everything is reducible to an idea. Third, if all we know is ideas, we cannot get beyond these ideas to know whether a real world exists beyond our ideas. In contrast to common sense realism where error is admitted, this theory undermines all of knowledge since it cannot get beyond the datum or image to examine the world.

Fourth, a similar objection is raised by Montague which he regards as destructive to the view. It centers on the difference between perceived-objects-in-space and the real space. Since I know only the objects that I perceive by means of datum I infer a real object behind them. "The inferred table, then, exists in a space other than the space of the perceived table."6 But "the only space I can possibly conceive is the space I perceive--the space, that is, in which the perceived table and the other sense-data are located."7 The space I perceive is subjective and I must try to look behind it for the space in which the objects can exist. But this is impossible and a space beyond the perceived space is "utterly meaningless."8

Because of the inadequacies of this view, we must turn to the next position growing out of response to it.

C. Berkeley's Immaterialism

The view of the English philosopher, George Berkeley (1685-1753) may be designated by several terms, subjectivism, epistemological monism, as well as immaterialism. A crucial question for philosophers in his time was: "how can a material object influence a mental subject?" Other philosophers had not been able to answer the question. Berkeley does not answer it either but he rejects the necessity of the question in his solution to the knowing experience. Some of his beliefs are as follows:

(l) Berkeley gave attention to the use of words. What meaning is there in the word "existence?" What do we mean when we say that something exists? Berkeley's answer is that when we say something exists it is perceivable. If I say that a bed exists in the room upstairs, I mean that when I walk upstairs into the room I will see a bed. Thus the existence of something means that I perceive it or can perceive it. Although Berkeley's view is called immaterialism he claimed strongly: "Let it not be said that I take away Existence. I only declare the meaning of the word so far as I can comprehend it."9 Berkeley's famous Latin phrase has been used to state the relationship between the existence of an object and the perception: esse est percipi--to be is to be perceived. This is the usual formula but it is not the full formula. The above Latin statement is used concerning sensible objects or things, but the full formula (esse est au percipi au percipere) means that "existence is either to be perceived or to perceive."10 Thus there are unthinking objects that the mind perceives, but there are also minds that think or whose "existence is to perceive rather than to be perceived."11
(2) Berkeley rejected the distinction between primary and secondary qualities as traditionally associated with John Locke. He has a famous passage saying:

I see this cherry, I feel it, I taste it; and I am sure nothing cannot be seen, or felt, or tasted; it is therefore real. Take away the sensations of softness, moisture, redness, tartness, and you take away the cherry. Since it is not a being distinct from sensations; a cherry, I say, is nothing but a congeries of sensible impressions, or ideas perceived by various senses; which ideas are united into one thing (or have one name given them) by the mind; because they are observed to attend each other. Thus when the palate is affected with such a particular taste, the sight is affected with a red colour, the touch with roundness, softness, etc. Hence, when I see, and feel, and taste, in sundry certain manners, I am sure the cherry exists, or is real; its reality being in my opinion nothing abstracted from those sensations. But if by the word cherry you mean an unknown nature distinct from all those sensible qualities, and by its existence something distinct from its being perceived; then indeed I own, neither you nor I, nor any one else can be sure it exists.12

(3) What then is in existence? There is nothing in existence, for Berkeley, called matter. What we popularly call matter, "an inert, senseless substance in which extension, figure, and motion, to actually subsist" is nothing more than "ideas existing in the mind."13 Berkeley came to this position by noting that if a secondary quality, i.e., color, exists in the mind only, then surely the primary qualities exist only in the mind also. He noted:

But I desired any one to reflect and try, whether he can by any abstraction of thought, conceive the extension and motion of a body, without all other sensible qualities. For my own part, I see evidently that it is not in my power to frame an idea of a body extended and moved, but I must withal give it some color or other sensible quality which is acknowledge to exist only in the mind. In short, extension, figure, and motion, abstracted from all other qualities, are inconceivable. Where therefore the other sensible qualities are, there must these be also, to wit, in the mind, and no where else.14

Consequently, if all that we experience is ideas, we cannot get beyond the ideas to see if there is a material world. It becomes meaningless to talk about a material world when all that we experience is ideas. This is why Berkeley's view is sometimes called immaterialism.

(4) So-called things are really, then, ideas. Before the reader concludes that Berkeley rejected trees, stones, seas, and sounds, he flatly said, "I do not argue against the existence of any one thing that we can apprehend, either by sense or reflection."15 He preferred the word "idea" to "thing" because "thing" implies something "existing without the mind."16 If one wanted to call objects "things" according to popular use it would be acceptable, but the customary way of speaking must not lead to the conclusion that things exist independently of being known. The next two points are linked together.

(5) All ideas are in a mind and nothing can exist that is not in a mind. (6) The reason something is in my mind is because it is in God's mind first. Both of these ideas can be seen in the following quote from Berkeley.

. . . all the choir of heaven and furniture of earth, in a word, all those bodies which compose the mighty frame of the world, have not any subsistence without a mind, that their being is to be perceived or known; that consequently so long as they are not actually perceived by me, or else subsist in the mind of some eternal spirit; it being perfectly unintelligible and involving all the absurdity of abstraction, to attribute to any single part of them an existence independent of a spirit. To be convinced of which, the reader need only reflect and try to separate in his own thoughts the being of a sensible thing from its being perceived.17

It must be kept in mind that a thing does not exist because God perceives it, but God perceives it (in a creative sense) and it then exists.

Berkeley anticipated a number of objections to his views. He argues that his view is not impractical although it sounds thus at first, it is not skeptical or unscientific, nor did it reduce everything to illusion.18

Probably the most easily misunderstood point is the summary statement: "to be is to be perceived." When one applies the statement to conclude that what is not perceived by me does not exist, then it appears absurd, particularly from the human vantage point. Berkeley would not admit that when one leaves a room and no one else is in it the room disappears. This cannot happen for there is continuity in nature and continuity is guaranteed by the Supreme Being who is the originator of our ideas as well as the Knower who causes all things to continue to be. Thus the statement "to be is to be perceived" applies ultimately to God's perception. The issue in Berkeley has been made famous in two limericks:

There once was a man who said, "God
Must think it exceedingly odd
If he finds that this tree
Continues to be
When there's no one about in the Quad."

"Dear Sir, Your astonishment's odd,
I am always about in the Quad
And that's why the tree
Will continue to be,
Since observed by Yours faithfully, God."

There are two criticisms, among others, that are levelled against Berkeley's views. First, his views involve what has been called "the egocentric predicament."19 This means that I can never perceive unperceived objects because the moment I perceive them I make them automatically a part of my perceptive life. Hence I can never get beyond these perceptions to know if anything exists unperceived. Everything that I know automatically exists. Hence it is impossible to establish the statement that nothing exists unperceived.

The second criticism relates to Berkeley's appeal to God as the guarantor, foundation, or source of ideas. Berkeley avers that God can be known but it is in terms of effects. One does not see God per se but his effects. From the effects or activities in nature one may be said to see God. He wrote, "We may even assert, that the existence of God is far more evidently perceived than the existence of men; because the effects of Nature are infinitely more numerous and considerable, than those ascribed to human agents."20 Whether this solution is adequate will depend upon the reader's attitudes toward the so-called arguments for the existence of God.21

In summary, we must consider where we have come. In Berkeley, the objects of knowledge are known directly in the experience of the person. In this position, there is a kinship to common sense realism in that the directness is emphasized, but they part company on the nature of matter. There is agreement between Berkeley and representational realism in asserting that objects are states of consciousness but they part on the status of what is represented to consciousness: representational realism retains its materialism whereas Berkeley opts for immaterialism.

D. Phenomenalism

Phenomenalism is an outgrowth of Berkeley's views. Certain of Berkeley's views are accepted although part of his conclusions are rejected. Phenomenalism arose in reaction to Berkeley. The first chief advocate of phenomenalism was David Hume who is the father of the movement by virtue of his reaction to Berkeley. Later Kant gave the movement qualified support.

Phenomenalism accepted, first, Berkeley's analysis of the knowing experience. When I say I see a table I have an idea of the table in my mind and experience. What appears to me as a table is one and the same table. One cannot get back of the sense datum and examine to see another table which would be the alleged "real" table.

Second, the view of Berkeley that "to be is to be perceived" is accepted in one sense but rejected in another. When the phrase is applied to sense data as in the eyes, it is accepted--that is, a datum or image must exist to be perceived, but when applied to the existence of an object, it cannot mean that the object's existence depends upon being perceived.

When the phenomenalist says that something exists, he means that if you set up the right circumstances, you will have the sensation of experiencing the object. The statement "there is a green station wagon in my garage" means that if you raise the garage door and look in, you will see a green station wagon.

On the other hand, phenomenalists reject certain of Berkeley's views. The idea that physical objects do not exist unperceived is replaced by the independence of the existence of physical objects. That is, they are independent of any knowing mind, even God's. Berkeley's view that reality is purely mental is also rejected for a reality that is purely physical but that is seen and interpreted mentally. The need of God in Berkeley's theory is rejected in somewhat the same category that Locke's mysterious substance behind objects was rejected. In this regard phenomenalism agrees with Berkeley that what is experienced is real and there is no attempt to get behind the sense data to something else. Phenomenalists believe that something continues to be without God as the cause of it.

Phenomenalism needs to be distinguished from certain other views previously referred to in the early parts of this chapter. It differs from common sense realism in that it claims only to see sensations or sense data, or images, but not the object. It differs from dualism in that dualism involves a gap between the sense data and the object behind the sense data. Phenomenalism defends only the sense data as the object and behind that there is no other object to be sought.

From Hume's thought one may turn to Immanuel Kant. Kant published his work, The Critique of Pure Reason in 1781. Kant argued that man's knowledge of reality is limited to appearances or phenomena. Kant accepted a dualism in the knowledge situation. First, there is what we see in terms of perception and this is all we ever see. This gives his theory an empirical element. But back of what we see is a reality, described by the German term Ding an Sich, or translated into English as "the thing in itself," also called noumenon. The noumenon is never seen but is inferred from the senses related to the phenomenon. Kant wrote:

Appearances are the sole object which can be given to us immediately, and that in them which relates immediately to the object is called intuition. But these appearances are not things in themselves, they are only representations, which in turn have their object--an object which cannot itself be intuited by us, and which may, therefore, be named the non-empirical, that is, transcendental object = x.22

Although Kant is classified as a phenomenalist by many writers, this is not the whole story, and it must not be overlooked that Kant stands in the idealist tradition. The knowing situation requires something more than a matter of perception for Kant. Perceptions not only have to be interpreted, but the mind itself takes an active role in imposing meaning on the world that is perceived in the representations. Kant regards his new approach as a Copernican revolution in philosophy. He noted:

Hitherto it has been assumed that all our knowledge must conform to objects. But all attempts to extend our knowledge of objects by establishing something in regard to them a priori, by means of concepts have, on this assumption, ended in failure. We must therefore make trial whether we may not have more success in the tasks of metaphysics, if we suppose that objects must conform to our knowledge.23 (italics mine)

This moves Kant in the direction of idealism, but his distinction between appearances or representations and reality behind the representations place him in the phenomenalist camp on this point.

Various forms of phenomenalism have been advocated since the days of Hume and Kant. A modern version has come to be called linguistic phenomenalism. It is associated with A.J. Ayer. Linguistic phenomenalists argue that perception is one rather than two in its make up. One cannot talk about physical objects versus sense data. The linguistic aspect comes in the many ways of describing what is seen. A phenomenalist will maintain that

every empirical statement about a physical object, whether it seems to refer to a scientific entity or to an object of the more familiar kind that we normally claim to perceive, is reducible to a statement, or set of statements, which refer exclusively to sense-data.24

Thus the linguistic phenomenalist does not debate whether objects exist or not, but only about the sense-data and statements interpreting the sense data. These statements are hypothetical for the most part. Thus, if I state that an oak tree is in my backyard while I am not able to see it, I am stating
a hypothesis that if you go into my backyard under
normal conditions you will have a sense data of an oak tree.

The modern form of phenomenalism seems to bring considerable certainty to the matter of perception, for after all, a sense datum that I have appears to be quite certain and almost infallible. But there are serious problems with linguistic phenomenalism. First, while I claim certainty for my sense datum, I cannot claim certainty for my linguistic statement about it. The precision of statements about sense data is totally lacking and there are varieties of sense data-statements about the same data in different people. Hence, it is not an answer to the problem of skepticism which is needed.

A second charge against phenomenalism is that it implies a continual regression from the statement about the sense data to other qualifying statements which in turn are in relation to other statements. When I declare I see an apple, a red-sense datum, I must declare when I sense it, where I sense it, and the conditions under which I sense it.

In conclusion, we quote Ayer in his objection to phenomenalism, a view he once held but came to reject:

If the phenomenalist is right, the existence of a physical object of a certain sort must

be sufficient condition for the occurrence, in the appropriate circumstance, of certain sense-data; there must, in short, be a deductive step from descriptions of physical reality to descriptions of possible, if not actual, appearances. And conversely, the occurrence of the sense-data must be a sufficient condition for the existence of the physical object; there must be a deductive step from descriptions of actual, or at any rate possible appearances to descriptions of physical reality. The decisive objection to phenomenalism is that neither of these requirements can be satisfied.25

E. Phenomenology of Perception

Up to this point we have been dealing often with extremes. There are two opposites. First, there is Descartes, of whom we have said little, who began with the inner self, the cogito, and argued that "clear and simple ideas" are certain, but these are solely within the world of mind and reason. As long as we are in the world of reason, there is certainty, but when one turns to the world of the senses and seeking knowledge through the senses,
rather then reason, than skepticism gains a foothold. The senses are not reliable for certainty. They can be fooled and distorted. So Descartes gave us one side of the extreme which is called the rationalist approach. Second, the other side is the empirical approach which was emphasized by Locke and

Merely looking at something does not reveal what it is. Judgement is required. In some experiences the mind must gather all the data and only then can it "see" what is before it. In a sense the mind projects meaning. See the picture below. Can you see the picture of the head of Christ.

Reprinted, courtesy Ralph E. Dennis, Olathe, Kansas.

Hume, and they began with the senses. The senses
are the only source of knowledge about the world, but these philosophers were also skeptical about the senses. Since both camps are skeptical about the senses this leaves the status of knowledge in a less than hopeful situation.

This is complicated by one other twist. In Descartes' view of the self and reason, knowledge was secure as long as it was confined to the inner mind. Because of the unreliability of the senses, there was no sure route to the world outside the mind. On the other hand, the empiricists had a different kind of problem. Since they emphasized the sense approach to knowledge, they had an avenue to the mind or the self, but their sense-perception standard of knowledge would not allow them to defend a belief in a self that could not be seen by the senses. This was particularly true of Hume.

However, it seems obvious that both the body and self need one another. One modern philosopher who formulated an answer giving credibility to a body and a self is Maurice Merleau-Ponty who published his definitive work, The Phenomenology of Perception. While the title sounds formidable, it is a thorough study of perception and our knowledge-experience. Several points may be made to give something of the emphasis of his work.

1. Knowing is much more than sensationism. Sensationism is built on simple, pure sensations, like a picture coming to the film of a camera. It implies an atomistic approach to seeing one thing at a time in succession. Now knowing is much more complex. There is no such thing as a "pure" sensation and the analogy of a camera is misleading. Even if one could reconstruct an image reflected through a lens onto an object, or film, this is not like experience. This attempt at the camera analogy overlooks three elements in our knowing experience: (l) who determines what image is to be reflected, (2) what is the meaning of the image reflected, and (3) there is no basis for understanding what a "field of vision is."26

Sensationism is meaningless apart from the process of interpretation which involves the idea of mind or person. A simple sensation means nothing more than I see a "something." The sensation does not tell me what the something is. Any sensation must be received by the mind which gives it a meaning. The sensation does not interpret itself. The who receiving the sensation is most important and bears no analogy to the film of the camera. The camera is directed by a mind who chooses the sensations to be captured on the film, but the film does not know what it has done and why.

A further problem arises from sensationism, or simple empiricism. If I am the collector of simple, pure sensations, there is no way to explain the identity between apparently similar experiences. For example, I see a tree. Now I close my eyes for a moment. Now I open them again, and look at a tree. Is this the same tree? My common response is yes, but this is based upon something more than the sensation itself. What was there beyond the sensation that identified the two sensations as the same? Certainly the sensations did not do the interpretating themselves. There is a continuing element in my being that is called person that receives the sensations of the two experiences of the tree. But I cannot affirm this "person" of my being by sensation. I make the judgement that it is the same tree without justifying my judgement. Hence, there is no pure sensation, and sensationism is not the place to begin for an understanding of knowledge.

2. Knowing centers around attention. Attention plays no role in the two opposite views we have described above, empiricism and rationalism. Merleau-Ponty notes:

Empiricism cannot see that we need to know what we are looking for, otherwise we would not be looking for it, and intellectualism fails to see that we need to be ignorant of what we are looking for, or equally again we should not be searching. They are in agreement in that neither can grasp consciousness in the act of learning.27

In the common experience of a day, a person encounters many diverse objects, people, and events. Sensationism per se, has no rationale for giving attention to one object or another, one person over another, etc., but the fact is that attention is focused, and where it is not focused, inattention causes us to make mistakes to our regret.

Consequently, we have to describe knowing in terms of attention. Attention is related to a field. Many objects may be in the visual field of the person that do not gain his attention. Attention on an object is focused by motivation or intention. When I go into a crowded auditorium my visual field incorporates many people to which I give no response. But when my eye encounters a familiar face I respond with a smile, a hello, or a wave of the hand.

Attention and Intention can be seen in a different way. A playful boy standing in the yard is not the same for our attention and intention as a boy lying wounded near a crushed bicycle on the street. The difference of focusing our attention and intention on the two different pictures is related to the driving force behind attention and intention. That involves our third point.

3. The body is "subjectivized" or subject filled. The body is that "by which there are objects." My body, however, is never an object to me. It is the necessary condition for objects. But it is not mere body that is affirmed. Remember that empiricism could only talk about bodies, and rationalism could only talk about consciousness or mind. The point of Merleau-Ponty is that the body is filled (incarnate) with a subject--me! My body is inhabited by me. There is no part of my body which does not relate to me. Without my body I would not know the world as I now know it. Merleau-Ponty introduces the idea of "body image" which means that "I have an undivided possession of the parts of my body, for this image envelops them."28

Now we must link up the idea of an embodied soul or person with the element of intention. Intention focuses upon the object or experience. Without intention, there is not much that can be known. This is illustrated in two examples from clinical studies that Merleau-Ponty relates. First, consider sexuality. Unless one can say either tacitly, or verbally, "I intend sexuality" one is impotent. This is to say that sexuality involves more than physical fitness. The clinical study of the patient Schneider shows the example of a man who had the physical ability to engage in intercourse, but who did not have the intention. He can engage in intercourse if his partner initiates it. Kissing is not meaningful to him and erotic literature has no arousing effect. In a non-clinical application, it is still true that sexual impotence or frigidity is not due usually to physical inability, but to a loss of intention. There may be many factors involved in the loss of intention but they will not be physically oriented.

The second area is speech. Schneider has a stock of words of verbal images and he has a stock of thought categories (the empiricist and intellectualist interpretation of speech respectively), but what he has lost is a "certain way of using them." In common every day experience the certain way of using them involves intention. A man may know most of the words of the dictionary but have nothing to say. If he does speak, he does not start with Aachen and end every sentence with zymurgy. If speech is to have meaning, it must convey meaning, not just words, or isolated concepts. The key to speech is the subject-filled body with intention as part of its nature.

4. The body involves synaesthetic perception. This involves several things. First, perception has been mislead by the tendency in physics to isolate one sense at a time for study. This is artificial and damaging to a sound theory of perception. Instead, a synthesis takes place in perception. One sense affects other senses. Color, for example, elicits motor responses in patients. "Habitual positions of limbs are modified, movements are smooth or jerky according to whether surroundings are either blue or green on one hand or red or yellow on the other."29

Second, perception involves the whole body. There may be a primary sense used, but that sense is translated to the other senses. "Synaesthetic perception is the rule" but we are unaware of it only because the physicists have influenced our organization of the experience. Merleau-Ponty said:

The senses intercommunicate by opening on the structure of the thing. One sees the hardness and brittleness of glass, and when, with a tinkling sound, it breaks, this sound is conveyed by the visible glass. One sees the springiness of steel, the ductivity of red-hot steel, the hardness of a plane blade, the softness of shavings . . . .30

The body synthesis that goes on between the senses helps to illustrate the meaning involved in a phenomenal field. My bodily being is the means to knowing things. But where there is no full synthesis of the senses, knowledge breaks down. This happens in people born blind. Tactile information has been available, but the eyes have never functioned. A blind person may know a circle by running his fingers around a circle. When vision is then restored by surgery, the patient never knows what he sees. His hand is described as a moving white patch and a circle is "seen" (comprehendingly) only when his eyes follow the outline of the circle and synthesizes the information already known by the hand.31 In this regard Merleau-Ponty explained:

These remarks enable us to appreciate to the full Herder's words: Man is a permanent sensorium commune, who is affected now from one quarter, now another. With the notion of the body image, we find that not only is the unity of the body described in a new way, but also thru this, the unity of the senses and of the object. My body is the seat or rather the very actuality of the phenomenon of expression, and there the visual and auditory experiences, for example, are pregnant one with the other, and their expressive value is the ground of the antepredicative unity of the perceived world, and through it, of verbal expression and intellectual significance. My body is the fabric into which all objects are woven, and it is, at least in relation to the perceived word, the general instrument of my comprehension.32

5. The visual field makes sense out of sense. The problem of depth in perception was a difficult one for traditional explanations of knowing. Since the retina can only receive a flat projection, how can depth be understood? We obviously perceive it. But the traditional theories could not explain how an object appeared so big up close and so little so far away. The object did not change in shape. One answer was that depth is just like breadth, but seen from the side, but even then it was never seen. Moreover, it didn't really explain anything.

With the understanding gained from the visual field, an answer is in the making. The visual field is the sum total of my area of perception as viewed with my eyes. When a man stands 3 feet in front of me, he occupies a large space in my visual field. He may be a large fellow and be almost all of what I see before me. But if he stands a thousand feet away from me, he occupies a proportionately smaller area in my visual field and "appears" to be smaller. Consequently the visual field gives an understanding to depth-distance that

other theories could not. This removes some of the alleged contradictoriness of the senses.
6. The body subjectivized restores integrity to the knowing experience. The attack upon the senses led to skepticism. The past experience of philosophy has revolved around the either/or game of being absolutely certain or absolutely ignorant. The issue is neither extreme, but "what do I know?" Because I am an ensouled body, I am consciousness, a person. At the same time, my body inhabits space and time. I fill my body and my body is close to objects around me. "I say that I perceive correctly when my body has a precise hold on the spectacle."33 I may be deceived momentarily (or longer depending on the experience) by thinking that phantasms or illusions are overtaking me when something looms in my visual field, but only to learn instantly that it was a fly near my eye and it was not as threatening as I thought. My body was deceived momentarily, but my body also corrected the deception.

The study of Merleau-Ponty leads to the conclusion that knowing is more direct and true than previous theories have granted. Instead of maintaining "I see an ash tray" philosophers have admitted only that one can say "I think I see an ash tray." But in the normal sense of the word "see" it must be admitted that "I see an ash tray" stands without contradiction.34

Another implication of being a subject-filled-body is the possibility of extending myself through various instruments. As I sit typing, the typewriter has become a part of myself. I am not conscious of it, nor the mechanics of typing. I will, or intend to type and I do it. Very much like the movement of the hand, I will or intend the action and it happens. Similarly, the blind man's cane is an extension of his body and the cane serves the same purpose as a finger or hand.

In conclusion, it may be said that phenomenology of perception offers a whole view of man. As such it does not have the one-sided qualities of previous theories. While it appeals to classic sources for data to support its contention, it claims to have a great kinship to common sense experience. Philosophers have been inclined to one-sided views that have removed them from possibly solving the problems at hand. Doing a phenomenology of perception has retained the contributions of empiricism and rationalism without the barrenness of their restricted positions. A study
of the whole man--embodied, incarnate ego--has put perception and knowledge on a firmer foundation.

Summary and Conclusions

We have traced the issue of knowledge particularly as it relates to perception from common sense realism to a phenomenology of perception. The following chart may help to organize the different views.

What is Seen? Problems
Common Sense Objects seen Error is difficult to
Realism directly explain; senses

Representational Objects seen Skepticism because Realism indirectly; of the senses;
primary and skepticism about
secondary qualities world behind
of Locke images

Immaterialism See objects or Requires God for
ideas directly; foundation of
see only ideas ideas known

Phenomenalism See indirectly Skepticism about
because of ideas; the world behind
ideas reflect images or ideas;
the world rejects God as
cause of ideas

Phenomenology of See directly Error is possible,
Perception but correctible;
confidence in knowing the world

We have seen problems in each position. Any theory of knowledge must give credence to the senses, the knowing subject, and provide a synthesis of the different facets of man's experience. A study of perception along the lines developed by Merleau-Ponty seems to do this with the greatest advantages. While this may not be completely without questions, his view helps to remove the shadowy world of unknowns behind sense data and at the same time give credibility to our knowledge of ourselves as well as objects in our world.

For Further Reading

Ayer, A.J. The Problem of Knowledge, Baltimore: Penguin Books, 1956.
Berkeley, George, The Works of George Berkeley, London: Nelson, 1949.
Eddington, Arthur, The Nature of the Physical World, New York: Macmillan Co., 1928.
Kant, Immanuel, Critique of Pure Reason, New York: St. Martin's Press, 1929.
Merleau-Ponty, Maurice, The Phenomenology of Perception, London: Toutledge and Keegan Paul, 1962.
Perry, Ralph Barton, Present Philosophical Tendencies, New York: Longmans, Green and Co., 1912.


1This is substantially the illustration of Sir Arthur Eddington, The Nature of the Physical World, New York: The Macmillan Co., 1928, pp. ix-xii.

2Cf. Capaldi, op. cit., p. 35.

3Trueblood, Titus, Montague, etc.

4A.J. Ayer, The Problem of Knowledge, Baltimore: Penguin Books, 1956, pp. 113ff.

5Ibid., p. 114.

6Montague, op. cit., p. 262.


8Ibid., p. 263.

9Frederick Coopleston, A History of Philosophy, Vol. V, Part II, Garden City: Image Books, 1964, p. 26.

10Ibid., p. 27.


12The Works of George Berkeley, edited by A.A. Luce and T.E. Jessop, London: Nelson, 1949, p. 249.

13Ibid., pp. 44-45.

14Ibid., p. 45.

15Ibid., p. 55.

16Ibid., p. 57.
17Ibid., p. 43.

18Berkeley was attacked from many sides and the most famous, but unconvincing was that of Samuel Johnson who heard Berkeley preach on immaterialism. Johnson is said to have kicked a stone with mighty strength and exlaimed: "I refute it thus."

19Ralph Barton Perry, Present Philosophical Tendencies, pp. 129-132.

20Ibid., p. 108.

21Cf. chapter 18.

22Immanuel Kant, Critique of Pure Reason, trans. Norman Kemp Smith, New York: St. Martin's Press, 1929, p. 136.

23Ibid., p. 22.

24Ayer, op. cit., p. 118.

25Ibid., p. 125.

26Maurice Merleau-Ponty, The Phenomenology of Perception, London: Routledge and Keegan Paul, 1962, p. 5. Merleau-Ponty's work is an excellent example of one who practices phenomenology in his study.

27Ibid., p. 28.

28Ibid., p. 69. The idea of an ensouled body, or a living soul, or embodied soul, is as old as ancient Hebrew thought. Unfortunately, Greek thought was the dominant influence in philosophical development concerning the mind-body problem. This was true even in the Christian tradition that should have known better. It is only in modern times that a recovery of this view of man has taken place in theology, psychology, and philosophy.

29Ibid., p. 225.

30Ibid., p. 229.

31Ibid., p. 223.
32Ibid., p. 235.

33Ibid., p. 297.

34Cf., p. 374.


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