Epistemology, or Human Knowledge


What do we know? How do we know it? What is truth? Can we know truth? These are just a few of the questions philosophy looks at in a branch traditionally called epistemology, from the Greek word episteme, or knowledge.

1. The Problem of knowledge.

Often the problem addressed is whether we can have certainty of anything, what are the certain principles of knowledge if any? Or, what is the real object of our knowledge? You probably believe you are sitting on a chair right now, you can see the chair, you feel it below you, your senses tell you you are in a chair, you have a mental concept of chair. Would you consider your level of certainty about the chair 100%? Maybe there a chance you are wrong, could you be dreaming, or hallucinating?

Or how is it that from some rudimentary basic sense data, such as sound waves from Rover's bark, and light waves from color reflected off Rover, and some chemical reactions in the nose that came from Rover's hair, we are able to have a unified and universal concept of the essence of “dog” and communicate this concept to another human by means of a word. We all claim to know things all the time everyday, so let us look at some theories of knowledge.

2. Conceptual knowledge.

There are different types of knowledge, so we must define what we are interested in. There are intuitions, or gut feelings, which are beyond the scope of this class. There is mathematical knowledge, which deals only in objects that exist in the mind, not in matter, for example a triangle, according to its perfect definition, cannot be found in matter, it is a being of the mind. There is sensible knowledge, the data of our senses, knowledge of material things. There is conceptual knowledge, a knowledge of the form or essence of things on a universal level, the type of knowledge of science, and is a part of daily life and philosophy. It is this last type we will look at here, the conceptual knowledge of the forms of things, that which is expressed in our symbolic language.

By observing what happens in children as they form concepts we gain some insight. By analyzing our own interior processes we gain some insight as well. But one of the most intriguing examples of this metal process comes from the life of Helen Keller. While most of us gain ideas and learn language spontaneously and without conscious effort as children, we do not remember what these early processes were like. But Helen Keller was deaf and blind from an early age, she did not have the same spontaneous and continuous growth as do most of us. For her, it all happened in a moment. Within a very short period of time one afternoon at the age of seven it all happened to her, the whole process contained in a condensed form. She was able vividly to remember this event and was able to pass it on to us in her writings. The heart of this mysterious event that took place in 1887 in Alabama is encapsulated in a few short paragraphs from her life story:

"The few signs I used became less and less adequate, and my failures to make myself understood were invariably followed by outbursts of passion. I felt as if invisible hands were holding me, and I made frantic efforts to free myself. I struggled–not that struggling helped matters, but the spirit of resistance was strong within me; I generally broke down in tears and physical exhaustion.

One day, while I was playing with my new doll, Miss Sullivan put my big rag doll into my lap also, spelled "d-o-l-l" and tried to make me understand that "d-o-l-l" applied to both. Earlier in the day we had had a tussle over the words "m-u-g" and "w-a-t-e-r." Miss Sullivan had tried to impress it upon me that "m-u-g" is mug and that "w-a-t-e-r" is water, but I persisted in confounding the two. In despair she had dropped the subject for the time, only to renew it at the first opportunity. I became impatient at her repeated attempts and, seizing the new doll, I dashed it upon the floor. I was keenly delighted when I felt the fragments of the broken doll at my feet. Neither sorrow nor regret followed my passionate outburst. I had not loved the doll. In the still, dark world in which I lived there was no strong sentiment of tenderness. I felt my teacher sweep the fragments to one side of the hearth, and I had a sense of satisfaction that the cause of my discomfort was removed. She brought me my hat, and I knew I was going out into the warm sunshine. This thought, if a wordless sensation may be called a thought, made me hop and skip with pleasure.
We walked down the path to the well-house, attracted by the fragrance of the honeysuckle with which it was covered. Some one was drawing water and my teacher placed my hand under the spout. As the cool stream gushed over one hand she spelled into the other the word water, first slowly, then rapidly. I stood still, my whole attention fixed upon the motions of her fingers. Suddenly I felt a misty consciousness as of something forgotten–a thrill of returning thought; and some how the mystery of language was revealed to me. I knew then that "w-a-t-e-r" meant the wonderful cool something that was flowing over my hand. That living word awakened my soul, gave it light, hope, joy, set it free! There were barriers still, it is true, but barriers that could in time be swept away. I left the well-house eager to learn. Everything had a name, and each name gave birth to a new thought. As we returned to the house every object which I touched seemed to quiver with life. That was because I saw everything with the strange, new sight that had come to me."
Helen changed from acting like a good responding animal, a dog of Pavlov so to speak, to a person with concepts, names for things, ideas and names that "meant" or signified the essence of the thing, not just meant to fetch or obtain that thing. She had concepts.

First we will look at two extremes among modern theories, Cartesian Rationalism, and Hume's Empiricism, then we will look at some theories that seek a middle way, Kant's Idealism and Aristotle's Realism.

3. Rationalism & Descartes.
On one end there is Rationalism, from the Latin word ratio, for idea or reason. Rationalists believe the only true, certain knowledge arises only within the mind, such as mathematical or logical formulas, without matter or senses. As we saw earlier, Plato was in this branch, or better said was the first to propose it. He insisted on years of math studies before philosophy, since it was the best preparation according to him. For Plato the world of senses held no truth. True reality is the realm of ideas (refer to section 2 in the Cosmology lesson). He would not say that sense data is unreliable totally, but just that it is not knowledge, it is only opinion. Only that which is eternal and unchanging is true. A truth about the sensible world, such as the wall being white, is changeable. Come back tomorrow and it could be yellow from a big water stain. Or maybe you see colors differently than others and do not know it. Therefore, only knowledge that does not rely on senses can be 100% true, all else may be 99% or less.

But rationalism really claims Rene Descartes as its founder and most important voice. Descartes lived in the 1500's and wanted to establish for himself what was absolutely certain. He felt all he knew was simply other people's point of view and he wanted to search on his own to find the most certain foundation, before he would accept anything else as certain. He wanted 100%. His method was complete and radical doubt of everything in order to find to undoubtable. First he doubted all sense data, since the senses can be fooled and thus sometimes be wrong. He doubted the existence of the outside world since it could all be a very realistic dream, the universe could all be in his head. He even doubted mathematical principles such as 2+2=4 since there could be a malicious spirit that deceives him into thinking such things, or a god that has us all just believing things that seem obvious but are not real.

Among all the doubt and deception he imagines, he then claims he has found his one certain foundation which cannot be doubted. No matter how deceived he may be, to be deceived he must exist. If he is thinking then he exists, he stated it, I think, therefore I am, Cogito ergo sum, which has become his famous saying.  (Although this line is not found exactly like that in his writings.)

He claims that since this idea of his own existence as long as he is thinking, is the only certain one, and its traits are that it is utterly clear and distinct, that the rule of truth must be that only ideas that are clear and distinct are true. This is the test. He then sees in himself a clear and distinct idea of a God, thus it is true God exists, and if there is a good God, then he would not be deceived always, God would not allow it, therefore obvious truths such as the existence of his body, about math and reality that are clear and distinct are true. In this way, through the "discovery" of innate ideas found in the mind, he felt he had grounded all he knew about the world on a certain foundation.

He is credited with starting a revolution in philosophy, he is called the father of modern doubt and rationalism. You will notice in his theory that contact with the outside world plays no part, his philosophy is not one of observing and studying like Greek thought was, but of shutting down the senses and looking only inward into the mind. Much of modern philosophy has turned away from reality since then, concerned only with the mind. Once finding your starting point only in the mind there is no "bridge" to reconnect to the world.

4. Empiricism.
The other extreme from rationalism is those that claim only sensible data is valid knowledge. The scientific advances in the time of Descartes and after gave rise to an opposing theory, that only the material data that we can verify with the senses is what can be known, that facts must be observable and testable. Any idea that has no sensible evidence is an invalid idea and should be discarded. These theories are called Empiricism. They say rationalist knowledge is meaningless since it tells us nothing new, to explain the definition of a triangle as having three sides adds nothing, it simply repeats what the word triangle means and was already implied in the word triangle. Some call these analytical statements. But to say the triangle is white adds some new detail not contained in the definition of the word, and it is verifiable by the senses. Some call these synthetic statements. Empiricist  say analytical statements are based on mental processes only and do not provide any real help. They are true, but they are not useful. They say only a synthetic statement is of any use in the real world.

John Locke was a proponent of empiricism against Descartes. He re-affirmed the mind had no innate ideas, the senses were the only source of gaining knowledge. But David Hume, who we saw when talking about proofs of a supreme being, goes farther. He says that as we directly experience something, such as the room we are in, we have an impression of it. Later when we think back on it we have a less clear memory impression which he calls an idea. Claims about ideas (our own or others) must be verified by returning to the impression. Any idea, or joining of multiple ideas, is only valid if one can return to an impression of it to verify. If I join two ideas such as gold and mountain to think of a golden mountain, this only has meaning if I can go out and find an impression of a golden mountain. Not only does all knowledge come from the senses, but only directly verifiable sense data is truly knowledge. Anything not directly sensible is not be accepted. Concepts such as cause, effect, self, essence, form, etc are all dismissed as irrelevant since they are not sensible. Have you ever smelled the “self”, or heard a cause? Therefore you cannot claim to know them since you have no sense impression of them, they are empty words according to Hume's radical skepticism.

But since the senses are not 100% of the time reliable (see examples in White pp. 292-295, and as Descartes pointed out) it leaves a standoff between rationalism claiming truth but without senses, and Empiricism claiming no truth, and the senses as the best probability.

5. Immanuel Kant.
There are some more middle ground theories that sought to explain knowledge, we will look at Kant's Idealism First, and then Aristotle and Aquinas' Realism. Immanuel Kant lived in Germany after Locke and Hume and Descartes, and tried to develop a middle way. His theory often called Idealism has been very influential and has often been credited with the current popularity of relativism in our current culture. He tried to solve the gap between rationalism and empiricism, by accepting both claims in a new harmonized way, but ended up leaving a very large problem with our knowledge still. Like Descartes he states that only ideas of pure reason could be certain, and like Hume claimed that sense data was the only source of it, but he came up with a theory that the mind does not just receive data from the senses, but that the mind is an active process that filters and rearranges or "recreates" the the data, imposing on the data categories such as cause, substance, time and space, necessity, contingency, unity and plurality, etc, that are not strictly sensible. So knowledge for Kant is the human being knowing what the mind has created and actively rearranged from its contact with reality. We know what our mind creates. Since we all have the same type of mind, we all experience reality the same way.

But the problem with Kant is that we do not ever know the actual thing in itself (ding an sich), we only know the thing as it appears, we know the image in our mind, created by our mind. We can never know the thing really as it is. So the result is similar to Descartes, the theory leaves man trapped in the mind unable to bridge out. And since everyone just knows what appears in their mind, then who can say everyone knows the same way, so who can claim any truth. The result is relativism.

6. Realism.
The textbook ends here, but we will continue on to look at the classical theory of realism which is generally the theory of Aristotle and the dominant theory throughout the centuries up till Descartes began to change  philosophy. It is sometimes called the Natural Theory, since it is the theory that everyone seems to live by, whether they accept it or not.

Realism approaches the problem differently. It is a middle way like Kant attempted, and it accepts some of both Descartes and Hume, both that we know certain truths mentally and that all knowledge starts from the senses. But to begin it does not accept the way Descartes poses the questions. If one accepts Descartes' idea that we must first prove we can know before we can move on to other knowledge and philosophy, then one is forever stuck in the mind. The way Descartes asks the question already accepts the conclusion. But Realism claims we are already knowing before we can even ask the question how knowledge is possible or if we can know. As soon as the mind is in contact with reality, we are knowing it, before we can even think to doubt anything, we must first acknowledge that we already know certain undeniable truths.

Those that claim we may be deceived by a malicious god, or may be simply a brain in a jar hooked to a computer (like the Matrix) are asking non-problems. They are totally hypothetical problems with no evidence or reason to suggest they are the case. Realism suggests we should look at how we actually live, and from there build a theory of how our knowledge works, find the data for study "ab actu" (from the acts), not think up bizarre situations to try to doubt everything. Realism means that what is real is what we perceive, and we perceive what is real. It does not blindly accept that all knowledge is correct, or that we are never deceived in our quest for knowledge or even often deceived, but recognizes that the mind naturally knows at least some truths, and thus must be capable of truth, and even incomplete knowledge is still knowledge, and even when we are deceived, we can often figure that out and correct ourselves.

7. Foundation of knowledge.
So what are the fundamental truths Realists claim we know? Well, from the first moment of contact of the mind with reality, the mind forms the idea of “being”, that “something is”. In this fundamental principle underlying knowledge, we grasp that the knower exists and the thing known exists. We grasp that to-be is not the same as not-to-be. From this we form the most fundamental principle of all human judgments - "The same thing cannot both be and not be at the same time in the same aspect." This is the basic principle of all judgments, the first truth known. Aristotle called it the Principle of Non-contradiction, not an innate idea, but a principle formed upon first contact with reality. An idea of reason like Descartes, but gained through sense contact with reality like Empiricists.

8. Truth.
So what does it mean that the mind is capable of some truth? What is truth? Rationalism held that truth was only the purely mental concepts such as self, or mathematical ideas, as the clearest ideas we have. Empiricism held that truth is only that which is verifiable by the senses, and even this is not 100% certain. Idealism held that we do not know the essence of anything in reality, we only know the appearance in our mind, with the result that  we cannot know truth in the classic sense. Realism defines truth as adequatio res et intellectus, or adequatio ens et mens, meaning conformity or correspondence between mind and things. This means that if the mind is conformed to how the thing is, then the mind has truth. There is an object of knowledge, a thing, and as we contact it the form of the object is received in the intellect as a concept, and is then judged to be a certain way. If the intellect's acts are in conformity with the object itself, then there is truth. Idealism, Rationalism, and Skepticism are all in some way reducible to relativism and go against the Principle of Non-Contradiction.

8. Stages of knowledge.
So what are the steps to knowing an object? Empiricists (such as John Locke) and Realists (such as Aristotle) agree that at birth the mind is a blank slate, a tabula rasa, that there is no innate or inborn knowledge, we are not born with ideas already, and that the knowledge we begin to accumulate all starts with the senses. But Empiricism holds only sense knowledge is valid, but realism teaches that although it starts with senses it does not have to remain there.

First are the five senses which are our means to contact reality and gather data. By means of smell, sight, hearing, touch, and taste, we receive input. These are the external senses. What they receive is sensation. The data is then organized by the internal senses, which are acts of the brain. As a cognitive being we first unify the various data from each of the external senses, so that it all relates to the one same object, this is often called 1) cognitive sense or perception. The brain also uses 2) imagination to to form a mental image of the object, complete the image and store it. The brain also has an 3) estimative sense which evaluates and values the object as helpful or harmful, comparing it to other perceptions to determine its usefulness. The 3) memory stores these evaluations and non-image data of the perceptions.

All the above process is not happening like an assembly line in order, everything is going on at once in a split second, and is going back and forth, sensing and perceiving the world around us. The result of these actions is a “sensible perception” or "sensible species", a type of sense data idea of the singular particular objects around us. This process is shared with animals who perceive in the same or similar sensory way.

Up to this point it is knowledge of a singular, such as “Rover” But Realism holds that as humans we also know in a universal way, we also know the form of “dogness” when we sense just Rover. The intellect reads in (intus = inside, legere = read) the sensible perception what is universal and intelligible, the essential aspects of the form, and brings it into the mind as a concept. This is called abstraction, (from ab-trahere, to draw out.) The mind draws out from the sense perception the form, without the matter. This action is beyond the animal level of knowledge and cannot be done by the brain alone. The faculty that does this "illumination" is called the active intellect. The brain is a fleshy organ, abstraction is an immaterial act making an immaterial and universal concept, it cannot be produced by matter. The intellect uses the brain, and relies on it since it can only know by means of the sensations and perceptions, but even though the intellect uses and depends on the brain, its action is its own, not an action of the brain. Once the mind has concepts, they can be considered in themselves as universal ideas, or compared to others to classify and define. This Realist refer to as passive intellect. Upon these concepts further reflection can be done, called second intentions.

So according to Realism and Aristotle knowledge starts with sensation, perception, then leads to abstraction and conceptualization. In this way the human knows singular sensible things and also universal conceptual things, always actively moving between both perceptions and concepts, back and forth in daily life.

9. Language.
Following the conceptualization, which is sometimes also called the internal word, we use an external word to comunicate the concept to others. Our words are artificial conventional signs that we use as signifiers of our ideas, and by means of words we can bring an idea we have in our mind to also exist in another person's mind. It is a triadic relation. The word indirectly signifies the things itself, and directly signifies the concept of the idea. The relation between the thing and the word is indirect, the concept is the bridge between them.

In conclusion, with the few theories we have seen we have covered a couple of extremes and a couple of middle paths to supply a basic understanding of how philosophers have understood knowledge and certainty. Look at your self, think deeply about the way you contact the world around you, since the way our minds think says something about what kind of being a human is. What kind of being you are.