[The following material includes parts of a lecture delivered by TA Robert Parks in 1997.]
An examination of John Lockes life provides many insights into his work. For us, it can give us a sense for why he asks the questions he does. Lockes magnum opus, on which he worked for 20 years, is his Essay Concerning Human Understanding. In the introduction he tells us that this essay is an attempt:
These concerns arise out of a particular situation, one that was expressed in Locke's own life in several ways.
The situation in which Locke found himself made these epistemological questions not just a matter of philosophic import, but a matter of practical interest. Lockes question of how and what we know was driven by the question of how we ought to live.
In fact, Locke says in the introduction to his Essay that the task to which he set himself in the Essay arose from a discussion of religious and moral issues. He and some friends were having a discussion and quickly found themselves beset by difficulties on every side, to the point that they could proceed no further. What they needed to do, said Locke, was first to consider the limits of human understanding. Then they wouldnt waste their time arguing over things that cannot be known. What this anecdote conveys, I hope, is that these epistemological concerns have practical import. They arise out of a time when friends no longer feel that they can appeal to traditional authorities to decide religious and moral questions. In order to answer these questions, says Locke, we must first answer the epistemological questions.
1. How do we understand?
Perhaps the place to begin is with the object of the understanding. Here is a point on which Descartes and Locke agree. Both insist that ideas are the object of understanding.
Locke also describes ideas as "whatever it is which the mind can be employed about in thinking".
When I contemplate this desk, or the people in this class, those things are not actually present in my understanding. What is present, says Locke, is a sign or representative of the thing Im consideringthese are the ideas.
So the question of knowing or understanding starts with the question of how I come to have these ideas in my head. Descartes argued that some ideas are innate. They are impressed upon every human being. But Locke finds the notion of innate ideas unsatisfying. First of all, he says, one would have to prove that there really are ideas which are universally accepted. But that cannot be proved because there are none. Even such ideas as that of God or the idea of whatever is, is are not universally acknowledged. Moreover, says Locke, even if one could prove that there were universally accepted ideas, that would still not prove they were innate. For instance, one might be able to show that they derived from another source.
Locke thinks he can show where these ideas come fromthey come from experience. When Locke says that all ideas come from experience he means they arise from one of two sourcessensation or reflectionand ultimately all ideas derive from sensation.
Sensible objects convey to the understanding certain distinct perceptions of things. For example, a piece of paper conveys the distinct ideas of rectangularity, thinness, smoothness, whiteness. When I look at a rose I receive the idea of its shape, its redness, its sweet scent. Locke says that some of the qualitiesor powers in things to produce perceptionsare primary and some are secondary.
Primary qualities are utterly inseparable from the thingthey exist in the thing whether we perceive them or not. Examples of primary qualities are solidity, extension, figure, motion or rest. The piece of paper has extension whether I perceive it or not. Secondary qualities are nothing but the powers to produce various sensationsthey are nothing in the objects themselves but produce various sensations in us by their primary qualities. They have no resemblances in the body of the object itself. Examples of secondary qualities are taste and smell, according to Locke.
Sense experience gives rise to the ideas in our mindssuch as ideas of extension, sweetness, bitterness, etc.
The second source of our ideas is reflection. In reflection the mind observes its own action. Observing the action of our mind when we reflect furnishes us with ideas of perception, thinking, doubting, believing.
Complex ideas: Locke argues that all knowledge arises from these two sources in a particular way. It begins with the simple ideas that come from sensation and reflection. Then, through the action of reason, these ideas are combined into complex ideas. So the simple ideas of the roses shape, color, sweet scent, and painful thorns combine to form the complex idea of the rose. Even the most abstract ideas have their origin in sensation an reflection.
2. What are the limits of knowledge?
Now that we know how we gain knowledge we can ask what are the limits of our knowledge. Locke says, first of all, that because the only immediate objects of the mind in all its thoughts and reasonings are ideas, our knowledge concerns only our ideas. Thus he defines knowledge as the "perception of the connection and agreement, or disagreement and repugnancy, of any of our ideas."
What is an example of such knowledge? I know that my idea of white and my idea of black are not the sameI know they dont agree with one another. I know that redness and sweet scent co-exist in the same subject, that is in the same rose.
Locke distinguishes three kinds of knowledge: intuitive, demonstrative, and sensitive.
IntuitiveThe clearest and most certain of all knowledge is intuitive knowledge. Intuitive knowledge occurs when the mind perceives the disagreement or agreement of two ideas immediately and of themselves. That is, it perceives the truth without the intervention of any other ideas. White is not black. A triangle is not a circle, three is more than two, I exist.
DemonstrativeThe next level of knowledge is demonstrative. In this case the mind does not bring ideas immediately together but judges their agreement or disagreement on the basis of intermediate ideasi.e., through reasoning. Though this knowledge can be as certain, it is not as "clear and bright" and the assent is not so ready as in intuitive knowledge. Locke thinks we can have a demonstrative knowledge of God.
SensitiveThis is knowledge of the existence and character of things external to the understanding. It is not as certain as intuitive and demonstrative knowledge, but allowed to pass under the rubric of knowledge. For example, the difference between perception of the sun by day and thinking on it by night expresses this type of knowledge (of the sun's existence and brightness). Likewise, the contrast between the pain of actually being in fire and merely dreaming of being in a fire signals the presence of sensitive knowledge.
Locke insists that the knowledge that comes in these three forms is extremely limited. In fact, we know very little through the things that are intuitively self-evident to us, through the things that we can prove by deduction, and through our knowledge that things present to our senses exist. Thus, to appreciate the limits of knowledge more precisely, Locke has to press further.
Consider, for example, Descartes' talk about mind and matter as different substances. What does Locke think that we can know about substances? Lockes answer is very little. When I prick my hand on a rose bush, I know that the rose bush exists. I am also aware of its primary and secondary qualities. I perceive that it is red, that it smells nice, that it is shaped in a particular way, and that its thorns cause pain. But I only know what my senses present to me.
For us, the primary and secondary qualities are embedded in a stuff "we know not what". This stuff, we know not what, is substance. Locke argues that the notion of substance arises because we cannot imagine how our simple ideas can subsist by themselves, so "we accustom ourselves to suppose some substratum wherein they do subsist, and from which they result; which therefore we call substance." Locke does not argue that there is no such thing as a substance; he simply argues that it is beyond our capacities to know anything about it. It is a very uninformative concept.
But what about the things we can know through science? Surely this will count as genuine knowledge, particularly given the major advances being made in science in Lockes time and his close relationship with important scientists. Surely he will consider science to be concerned with the obtaining of knowledge. Actually, Locke felt that science does not provide us with knowledge proper, but only with probabile belief. Why only probability? Science proceeds on the basis of the primary and secondary qualities of things. It does not and cannot determine the "real essence" of any particular thing, only that which it presents to our senses. Our experiential knowledge limits us to the properties of things and does not reveal the things themselves. Without knowing the real essences of things, we cannot have certain knowledgewe must proceed on the basis of probability.
The fact is that what counts as genuine knowledge for Locke tells us very little about the world. Particularly in practical matters, we must proceed without the benefit of certain knowledge.
3. How do we proceed when we dont have certain knowledge?
After all of this we are left with the fact that we just dont know that much with certainty. So, what can we do? How should we proceed? Locke says that we can and must proceed on the basis of reason and experience. Even if we cant have certain knowledge we can still do our best.
What constitutes doing our best? Locke announces three general guidelines for managing in the absence of decisive knowledge.
Remember that Locke began this epistemological investigation as a result of the difficulties he and his friends had in answering religious and moral questions. Now, as a case study, let us examine how Locke applied his epistemological answers to the question of religious knowing. For religious persons, what would constitute "doing our best"?
Locke acknowledges that there is some ground for natural theology (we can demonstrate the existence of God) but that many of the truths of Christianity exceed our reason. They are revealed. But how do we know what to believe and what not to believe? How do we know what is revealed? Locke insists that we must apply the principles of evidence, probability, and proportionality to our examination of revelation. We must look at both the content of revelation and the factuality of revelation. Locke states, "Whatever God hath revealed, is certainly true; no doubt can be made of it. This is the proper object of faith: But whether it be a divine revelation, or no, reason must judge." He lays down some guidelines for the task of discerning authentic revelation.
In relation to Christianity, Locke argues that "Jesus was the Messiah" is a revealed truth. What evidence do we have for believing this? The most important piece of evidence for Locke is the miracles of Jesus and the apostles. Those miracles provide evidence that their statements include genuine revelation.
It follows from all of this that, for Locke, faith is assent to a proposition not in virtue of demonstration but in virtue of the proposition's expressing authentic divine revelation. Reason is the final arbiter of whether revelation is authentic.
4. Evaluation of Locke's Position
Locke's view has a number of strengths.
Locke's view also has some weaknesses, or at least undesirable features.
Mary (shows excitement): "For what?"
Eli: "I am now an official member of the "Campus Champions of Knowledge for Living."
Mary: "Oh. . . Im not really familiar with it. . . but it sounds very interesting."
Eli: "You bet. CCKL. We promote useful knowledge, even right here on campus! Common sense. Utilize your life experience. That kind of stuff. Its catching on like crazy."
Mary: "Useful knowledge? How are you going to promote that? I mean here on campus. Wont people resist it?"
Eli: "Some do. But resistance builds morale, group cohesion. . . sparks interest in the general public. We dont mind resistance."
Mary: "I always do. . . It makes me feel people dont like me."
Eli (not really listening): "Experience. Thats the key to it all. Everything we know comes from our experiences. It makes sense when you think about it. Where else could we learn anything?"
Mary: "That part is reasonable. But, like, doesnt everybody already believe that?"
Eli: "Well, I dont know that they really think about it much. . . But they should. I tell you, it used to be a really hot issue. "
Mary (politely): "Yes? I havent read about it."
Eli: "Well, it was a while ago. Inane ideas versus experience. There were these people who believed that we had these strange ideas just built into our heads, so to speak. And they thought about those ideas and came up with even more weird ideas. They were the inane ideas folks. The other guys pushed experience. They realized that we depended on our eyes and ears and brains to do the work. No ready-made thoughts."
Mary: "I dont know. I dont think women look at it that way. I sometimes just feel things."
Eli (exasperated): "Of course you feel things, thats the point. Your senses are working all the time, and thats where you get your basic ideas. Then your brain works on those, and you notice your brain working, and that gives you more ideas."
Mary: "Well, you seem to have a lot of ideas already."
Eli: "I just got back from a big rally. The p-a system wasnt working very well, but I think I got it all. I even took a few notes. Great stuff. . . it won me over. So I joined up. . . Right away, as soon as the main speaker finished."
Mary: "What is that badge youre wearing?"
Eli (proudly): "Official membership pin. I got it in my introductory membership packet. Came with a copy of the monthly newsletter called The Empiricist . . . and a bumper sticker."
Mary (sighs): "I used to love to get those packets. I remember joining one club that was advertised on the back of a cereal box and--"
Eli (with dignity): "This is not a kiddy club. (Tone softens) Hey, want to hear our theme song? You can follow along. . . its here on the front page (hands Mary the newsletter)."
Mary (frowning): "The Empiricist. I hope you arent going to get involved in exploiting underdeveloped countries."
Eli (impatient): "No, no. It has nothing to do with colonialism. Now listen."
(sings the following to the tune of Lavenders Blue.)
Mary (reading along, breaks in): "Wait a minute. Thats innate ideas. I-n-n-a-t-e. It says right here."
Eli (grabs sheet): "Where. . . Yeah, youre right. I must have heard it wrong. Well, same difference." (He begins again)
(Mary joins in. They both sing the last verse with gusto):
The distinction between rationalism and empiricism can be overdrawn, as similarities between Descartes and Locke demonstrate. But the two styles of view can be meaningfully distinguished by their contention over:
1. The Epistemic Goal of Natural Philosophy
For rationalism (Descartes): to gain certain knowledge of the essential nature of reality
For empiricism (Locke): to gain probable knowledge of the world in so far as the limitations of our experience allow
2. Nature and Sources of Knowledge of Reality
For rationalism (Descartes): some knowledge of reality derives from innate, indubitable ideas
For empiricism (Locke): all knowledge of reality ultimately derives from experiencefrom the way it appears to us
3. The Nature of Reason
For rationalism (Descartes): reason is the means by which innate ideas are discerned, and then further ideas deduced according to self-evidently certain logical laws
For empiricism (Locke): reason is the means by which patterned relationships among the ideas of experience are discerned, and then further ideas deduced according to intuitively certain logical laws
Extreme empiricism (e.g. J. S. Mill): even the logical laws of the operation of reason ultimately derive from experience
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