EPISTEMOLOGY

             Epistemology studies the nature, sources, limitations, and validity of knowledge. The questions it asks itself are, How do we know, and how certain can we be of it?

             There are two main sources of knowledge: reason and experience. Although both sources would seem to be intimately involved in knowledge, historically the question has tended to divide philosophers into two camps: those who placed their stress on reason and those who placed it on experience.

             Philosophers who chose reason as our only trustworthy source of knowledge came to be called rationalists. These thinkers-Descartes, Spinoza, and Leibniz-shared a number of characteristics: they all lived in Europe; all believed that reason by itself is capable of arriving at a true knowledge of reality; all believed in the doctrine of innate ideas; their model of the perfect science was mathematics; and their test of whether our ideas are true or not is intuition: "the absence of doubt in the unclouded and attentive mind."

             Philosophers who chose experience as our prime source of knowledge came to be called empiricists. These thinkers-Locke, Berkeley, and Hume-also shared a number of characteristics in common: they all lived in Britain; all put their faith in experience as our main source of knowledge, doubting whether human reason is capable by itself of arriving at anything more than a few basic propositions about reality: all believed that the mind at birth is a tabula rasa, utterly blank of ideas; and their test of truth was external, not internal: Ideas are true if they correspond with what we can find in the outside world.

            Each school, by proceeding on its assumptions, arrived at a dead end. Rationalism professed absolute confidence in reason's ability to arrive at a perfect knowledge of reality, yet the results each rationalist achieved differed markedly from those achieved by the others. Descartes's reasoning led him to dualism, Spinoza's to monism, and Leibniz's to pluralism. Empiricism prided itself on its attachment to experimental science, yet in the end none of the major empiricists was able to give an intelligible account of some of the basic concepts underlying science itself. Locke had to admit that substance was "a something, I know not what"; Berkeley said that if we do not have an "idea" of the self we nevertheless have a "notion" of it; and Hume said that what we call causes are only a series of "loose" or "separate" events.

             lmmanuel Kant tried to rescue what was valuable in these two schools of thought by means of a new attack on the problem of knowledge. He came to realize that each school had arrived at an impasse because of a wrong assumption about the mind's relation to the world. If we are to understand how knowledge is possible, we must come to see, Kant argued, that the mind is not, as both rationalism and empiricism assumed, totally independent of the world of objects it tries to know but rather contributes something to that world. Kant tried to identify this contribution in the Critique.

             The Critique is divided into three main parts: the Transcendental Aesthetic, the Transcendental Analytic, and the Transcendental Dialectic. The first deals with the faculty of sensibility and shows how synthetic a priori propositions are possible in Transcendental Analytic, and the Transcendental Dialectic. The first deals with the faculty of sensibility and shows how synthetic a priori propositions are possible in mathematics The second deals with the faculty of understanding and shows how synthetic a priori propositions are possible in natural science. The third deals with the faculty of reason and shows how and why the a priori elements offered by it and the claims made on their behalf by traditional metaphysics are not possible.

             Although Kant's contribution to our understanding of these matters was profound much still remains unsettled and in doubt. As a result of these philosophic labors however we now see more clearly that the source of an idea cannot guarantee its validity (as rationalism had mistakenly believed); that the importance of empirical evidence lies not so much in being the source of ideas (as empiricism also mistakenly thought) as in being a means of testing and confirming them; that the process of information gathering, in order to be fruitful, must be guided (and Kant was right about this) by leading questions or hypotheses; but (and here is where he was probably mistaken) that the dream of an absolutely certain science built of synthetic a priori propositions is impossible.