The doctrine of realism is a common sense doctrine which postulates at least two things:
Locke is right that objects do not have color. Light has colors. Trees are green because they absorb all bandwidths except green, which they find useless.
Common sense realism i.e. naive realism is simply an unreflective, un-philosophical acceptance of the physical world as it appears to primitive men the nature of which is superficiality.
Is the shape of the penny circular or is it elliptical? OF course under a microscope a penny is neither circular nor elliptical but all across in every direction is rather bumpy like holey mountain ranges!
But I don't understand why that shows that objects have no color. What that is explains why objects have color. After all, not only are objects green because of the explanation you give, but also, because human beings have the perceptual faculties that they have. To say that a leaf is green is to say that under normal perceptual conditions, the normal observer will see a green leaf. That does not mean that leaves are not green. Rather it tells us what it means to say that a leaf is green. You don't want to say that when leaves are seen at night when there is no light that leaves are no longer green, do you?
Locke did not say that leaves are not green. He said that color is a secondary property. That is very different.
Color is a property of light, and not of things. Matter absorbs radiation, and what we see is what it cannot absorb. If it is a property of anything it is of the chemical structures in the matter. It is just easier to say a thing is green than to say why it appears green. It is not green, but its green color is a negative quality. Am I correct in saying that the colors it absorbs reflect its chemistry but the colors it reflects does not since many things appear green for different reason, that is, not the same chemical makeup? I do not know if it is true in either case. Things are green which appear green, but its greeness tells us very little after all. Emiting of light at a certain bandwidth is an atomic property, of bosons I believe. Colors do tell us something of atomic structure.
I think your point is wrong about things being green because of perception. First of all, it is not a tree falling in the forest. It reflects light when is gets light. But the light it reflects has an essential relationship to the light it absorbs. A plant does not see as we see, but in the sense that it follows the sun, uses all it can of the energy of the sun and then emits not only the most useless color to it, but to all other plants, and shades those beneith, in that sense I can say it sees light as well as us. It is not perception that makes things real, but our perception that gives them meaning. If there were no humans to sense time, space, color, or any other attribute of reality, it would still be there; but it would have no meaning. Life gives all reality meaning.
Pennies are circular, obviously. You seem to be assuming that unless a penny always appears to have the shape it actually has under all conditions of perception it has no shape. But that is absurd. The penny does have a shape. And it is the shape it appears to have under normal conditions of perception. Namely circular. The fact that a penny looks bumpy etc. has nothing to do with its shape. It can be bumpy, and still circular. Circular object may still be bumpy. The moon is quite bumpy. But it is accurate to describe it as circular, as contrasted (say) with triangular, or trapezoidal. Circular in shape does not mean, circular with no bumps.
Part of the difficulty lies as always with the truth, which is how we fairly represent reality. If you are using a descriptor, what is it good for? My example for this is quite common: The uterus is a pear shaped organ. So what is a pear? A uterus shaped fruit? There is nothing like the other except the earth, which is slightly pear shaped. Or is that uterus shaped? We try to tell the truth about reality. We should try to understand that knowledge color perception. When we know why reality seems as it does we see reality in a different light. And perspective colors perception. Not one thing on this earth will ever apppear the same to two people.
Do you really mean that leaves are not green in the summertime? I didn't say they were "green because of perception". In fact, I don't really know what that means. I said that they were green, and that what was meant by saying that leaves are green is that leaves appear green to the normal observer under normal conditions. So, to say that leaves have some mass is not to say that leaves appear to have weight to the normal observer under normal conditions, but (to repeat) to say that leaves are green is to say that they appear green to the normal observer under normal conditions. So we are distinguishing between two different kinds of property of leaves: secondary, and primary. But John Locke never said that objects have not color. What he did was to explain how it is that objects have color.
What has all that to do with the issue? The question is whether pennies are circular. The answer is yes, even if they do not appear circular under all perceptual conditions. The reason is that an object need not appear to have the shape it has under all conditions of perception. It would be interesting to ask why such a requirement has been imposed.
Pattern recognition is the key to our intelligence. Facial recogniton is essential for survival, or awarness of moods on a face. But this also extends to time. Since pennies and seasons are circular, though said cyclical, it also is percieved as a pattern. That is why what a thing appears to be is a requirement.
But it is not a requirement. No one thinks that any object has to appear the way it actually is in all circumstances. You don't, for example, think that an object looked at from a distance, must look the same size it does when you are near it, do you. That requirement, that an object must look the way it is through all conditions seems to have been imposed by philosophers. It is not a requirement of commonsense. As a matter of fact, if something looked the same under all conditions, we would suspect there was some trick going on. If a green object still looked green in the dusk, we would think that some artificial light was playing on the object, for objects do not normally look their real color when looked at in the dusk. A stick, half immersed in water may look bent (sort of, but not really, since it does not look the way a bent stick looks-not at all), but anyone who is above the age of 7 knows that the object is not really bent, however it may look like a bent stick.
I think these are all philosophical stories that are fed to us, and which no one who not has read them, even begins to believe. They just contradict the facts. Sticks half immersed in water simply do not look like bent sticks. Do they? And we expect objects to look different under different conditions of perception, without that meaning that some appearances are not their real appearances.
The fact that things look the same out of our sight, beyond our sight, and before we see them is essential to all rational understanding. It has a name, and it is a philosophical concept, but also a reality. In logic it is called identity, and in physics it is called conservation. All concepts represent conserved qualities. If they did not remain the same we could not recognize them, and could not name them. The difference between isolated phenomenon and examples of concepts is that they reoccur with the same attributes as before. In order to campare one example of a concept with another example of a concept the concept must remain unchanged. If you say one line is shorter than another you are able to compare them because each is conserved as a line, and the concept of line is conserved throughout. This means, for the purposes of philosophy that we are not comparing apples with oranges, but even more that we are not comparing one meaningless experience of a phenomenon with another just as meaningless.
We are able to recognize things as what they are by classification, that is by concept, such as 'leaf', or 'tree'. Everyone recogizes that thing change their appearance with distance or light; but they also recognize that they do not change their character with the circumstances. If we see a reed that appears as two reeds or as a sharply bent reed because of refraction, we do not need a concept to explain it to recognize that it is the same reed. Primitves fishing hit their mark with their spears because experience taught them where the fish was even without a scientific explaination.
In ever instance mind corrects for perception. We know the tree is green even in the dark. We only see it in the light, as it is the light we see. If the intellect could not distinguish one thing from another based upon experience we would be as blind as though we had no eyes at all. It is with imagination that we recogize things, but we do not verify with imagination. I can't even say that learning involves only one sense or the other. Rather, we see what we feel, and if it looks good we taste it. Some times that results in death, and everyone learns a lesson. So, we perceive withour minds and verify with our senses.
And what am I supposed to conclude from all of this? Is the leaf green or is it not. And do objects have real shapes that we observe or not? (I was under the impression that you said that leaves had no color. Now you say that (trees) leaves are green in the dark. Which is it?
The appearance of a leaf remains the same whether we see it or not. It is not perception that makes things real. We percieve much that is real with knowing where to look. We learn to distinguish between phenomenon, and mostly because they do not change. We do not affect the reality of things; but their meaning. And yes, leaves look green, but appear green because of what the plant is, because of a thing essential to the leaf, clorophil, which absorbs much of light energy but reflects green light. What a thing is in its underlying molecular or atomic structure is the why of its absorbing or reflecting light. The color found in white light that is reflected by an element is an attribute, a characteristic, or a quality of most things. So yes, I think it is entirely appropriate to say a leaf is green whether or not one understands that it is light that is green or any other color since the color a thing absorbs or reflects has a direct correlation with what it is. It is not its appearance that give it its reality, but its reality which give it an appearance. Things do not cease to be real because we no longer sense them, but they do lose their meaning when we can no longer sense them, as when we die.
Look. Something which may help here is something I learned about English in the process of trying to learn French. It is that the two most essential verbs in both languages are to have and to be, Avoir and Etre in French. And you will find in life that you are judged as often or as well on what you have in neglect of what you are. Some times these verbs are practically interchangeable. You can say: I have to go, or I am going. We say we are a certain age, and the French say they have a certain age. The two verbs are used to conjugate the other verbs. In the case of a leaf you can as well say it is green, or it has a green color.
What a leaf is, is why it is green in appearance. But things are not only their underlying structure, but all of the attributes that result from that structure. In the case of the leaf it is a reasonable conclusion that the structure followed from the energy it uses so that the light it rejects is essentially related to what it is. It is not arbitrary like a coat of paint, nor is it much useful since almost all leaves are green. I realize I am perhaps clouding the issue for you with every attempt to clarify. It is true that Color is a characteristic of visible light. If I say a tree is green, that is true of its appearance. If I say a tree is everything but green it is true to the facts because its primary source of energy, stored in carbon compounds that make up the tree, is from light waves which are not green.
The appearance of a leaf remains the same whether we see it or not.
I don't understand the above sentence. You mean that a leaf looks green even in the dark? That seems to me to be contradictory. The leaf doesn't look to have any color in the dark. And, if the leaf is not seen, then the leaf does not look green. But a leaf can be said to be green in the dark, and to be green when it is not seen. So, if you mean to say that the leaf looks green in the dark, that seems to me contradictory. And if you mean to say that the leaf is green in the dark, I agree with you, but I thought that you denied that. So you will have to tell me whether you are contradicting yourself, or whether you have changed your mind.
I think that a leaf is green in the dark, and when it is not seen, because I analyze the sentence, "the leaf is green" as follows: "the leaf looks green to the normal observer in normal conditions". And, even when the leaf is in the dark, or when the leaf is not seen, it is true of it that the leaf (would) look green to the normal observer in normal conditions.
It is true that what you write is "cloudy", and it is not helpful that it is so prolix. (Part of the reason for this is that you try to explain why the leaf looks green. I don't think that is necessary. I think you can take it for granted that educated people know about the physiology of the perception of color). It seems to me that the essence of what can be said about this, can be said quite briefly. That is what I have tried to do.
The doctrine of realism is a common sense doctrine which postulates at least two things:
1) The things in the physical world that we see and touch (or perceive in any other way) also exist when they are not being seen or touched or perceived. That is, things continue to exist in the same way even when we are not immediately aware of the things.
Also a stick when part of it is held under clear water appears bent. When we look at the stick in water are we looking at the real stick?
And also the same volume of water under certain conditions can feel cold to one hand and warm to the other hand.
Furthermore, how can colour be a quality "in" objects which themselves appear to be coloured in different ways, considering that the apparent colour of things varies with conditions of illumination as well as organic conditions (consider "jaundice", for example)?
The questions some philosphers have asked are: do we ever truly see a "physical penny" in itself at all? Do we ever really see a "physical stick" in itself at all?
So, what would a completely objective view of physical objects (a 'god's eye' view) look like? Can we have a true perception of objects?
The philosopher John Locke has maintaied that since qualties such as colour and temperature are dependent upon the subjective observer then physical objects do not posess these qualities of colour and temperature. He states that since physical objects in themselves (i.e. when they are not being perceived) have neither colour nor temperature, then what we perceive are ideas (sense data, or percepts) and not the physical objects themselves.
And whether or not our ideas (our sense data) of physical objects are said to actually correspond to those objects, they are, claims Locke, seperate and distinct from the physical objects. Locke is saying that what we perceive in our sense data is not the same as what real objects posess. Locke's theory is called representational realism also known as The Veil of Perception.
It was Kant who said that we can know nothing of things as they are in themselves. He said that we cannot have knowledge of things as they exists when we are not perceiving them. Kant says that we can only know the 'appearances' of things which he called 'phenomena". Kant says that since an object is distinguished by the time under which it is observed and the space in which the act of observations takes place, then the true nature of an object must exist only by abstracting the object from time and space, which is impossible for man to do.
Kant says that humans 'create' the categories of time and space and thereby falsify objects; since the true nature of the object in itself is bound up with universal causation. To perceive an object then is to falsely 'remove' it or seperate it from its millenial cosmic path of becoming in time and its necessary supporting materials in space.