One way in which modern philosophy, roughly that beginning with Descartes, is supposed to be different from what came before it, is its emphasis on the problems of acquiring knowledge. This emphasis on knowledge likely has its origins in a variety of circumstances.
One of these is the Reformation crisis concerning religious knowledge and related events. Luther questioned the Catholic criterion of religious knowledge - the Rule of Faith as it is called - and thereby started a new religion with its own criterion of religious knowledge. The Rule of Faith says that religious knowledged is determined by what Church fathers, Church Councils and the Popes say about any particular claim. Thus Church Councils have endorsed the doctrine of the trinity so anyone who claims that this doctrine is false is a heretic. Luther replaced the Rule of Faith with the claim that all Christians have the power 'of discerning what is right or wrong in matters of faith.' Luther finally made it clear that his new view amounted to this: What conscience is compelled to believe on reading scripture is true. This radical move changed Luther from just another reformer to the founder of a new religious sect. For many people it raised an enormous problem in regards to religious knowledge. Which of the two criteria was the correct one? It was difficult for people to determine the answer to this question. For various reasons, which we will consider, this skeptical crisis in regard to religious knowledge developed into a full blooded skeptical crisis about knowledge in general. So how does one acquire genuine knowledge?
One way to think about the problem of acquiring knowledge in terms of the era we are discussing is to regard reason, the senses and faith as competing ways of getting at the truth about reality. One might hold, with Plato for example, that the senses will not get one to the truth about reality; that only reason will lead us to knowledge of reality and how to lead the best life and attain genuine happiness. Or one might argue that the senses provide knowledge of the world that is more basic than anything which reason tells us. Or, one might hold that both reason and the senses are poor guides and that only faith will reveal the way things really are.
Skepticism is the doctrine that knowledge is not possible. One can be either a universal skeptic who holds that no knowledge whatever is possible (Could this be true?) or simply a skeptic about one faculty, like the senses, or some particular branch of knowledge, such as religious knowledge or mathematical knowledge. Skepticism is intertwined in the competition among the faculties because an advocate of reason, for example, is likely to be skeptical of the ability of the other faculties to reach the truth. The Cambridge Platonists, for example, regarded the doctrine that the senses are more important than reason as the philosophy of beasts. For men share sense knowledge with the beasts, while reason sets man apart from the beasts. An advocate of faith, on the other hand, will be skeptical of the ability of reason and the senses to provide genuine knowledge. The great French essayist Michel de Montaigne is an able and interesting advocate of this last view.
There are philosophers with much subtler views, who hold that there is a place and legitimate sphere for each of the faculties, and one must figure out what the limits are to each. Rene Descartes holds that reason is considerably more important than the senses in that reason provides more basic knowledge than the senses. It tells us about the essences of things, which the senses do not. Nonetheless, Descartes holds that the senses have a place in our scientific attempts to understand the world. Descartes also holds that various truths can only be determined by faith. John Locke also, seeks to determine the limits of human understanding, what we can know and why, what role the senses and reason play, and what can only be believed or taken as an article of faith. For Locke, the senses and reflection provide the materials on which reason works. Faith operates beyond reason.
Another strand which brought about the intense interest in knowledge was the extraordinary advances which were made during this period in mathematics and natural philosophy or science as we now call it. European mathematicians were finally able to surpass the results of the Greek mathematicians of antiquity such as Euclid and Archimedes. Similarly natural philosophers were coming to reject Aristotelian physics and Ptolemaic cosmology and geography. With the work of Copernicus, Brahe, Galileo and Kepler, astronomy and physics were put on a new footing. Surely, these extraordinary advances represented real knowledge. The struggle between skeptical arguments and scientific achievements, not to mention the claims of religion was a real one. One can see all of these concerns meeting in thinkers like Descartes and Pascal.
Philosophers during this era were obsessed with methods for discovering and presenting truths. A method, in this context, supposes some systematic procedure, which, if followed, guarantees that one will hit upon the truth and avoid error. One source of this interest in method is Greek mathematics. Euclid's Elements of Geometry and the works of other ancient mathematicians provided a model of knowledge and proof. How was this wealth of mathematical knowledge discovered? The demonstration of the theorems does not seem to provide much insight in answering this question. So, mathematicians and philosophers in the fifteenth and sixteenth centuries began reflecting on the method of discovery which they called the method of analysis. Essentially the view which began to develop was that one would take apart the thing which one wished to understand, until one reached the basic and essential parts composing it. One would then analyze how the parts relate to one another and put them back together. By taking them apart in this way and then putting them back together one emerged with a new understanding.
Galileo uses a method which he called the Resoluto-Compositive method. The whole which one is studying gets resolved into its parts and then put back together or composed again. This resolution into parts often involves simplifying and abstracting parts.Thomas Hobbes adopted this Galilean method to the study of man. Making the distinction between the complicated world in which their are good and bad, legitimate and illegitimate governments, and the state of nature in which there is no government is an exercise in the resolution of a whole into its parts. Once we see the nature of man in such a state, Hobbes thinks it becomes abundantly clear what the legitimate function of government is. We emerge from the exercise seeing clearly how to judge a good and legitimate government from a bad and illegitimate one. Locke and Spinoza, who both read Hobbes, perform similar analyses on the state, though with differing results. In the eighteenth century some of the analyses of the origins of language employ a similar method.
Descartes was extraordinarily interested in method. He wrote works like The Discourse on Method and gives quite remarkable examples of discoveries in geometry and other subjects which he claims were made on the basis of the methods he describes. In John Cottingham's book The Rationalists you will find chapter two devoted to a discussion of these methods in the works of Descartes, Spinoza and Leibniz.
In addition to the method of analysis, Descartes is famous for employing what has come to be called the method of doubt in the Meditations in order to try to defeat skepticism. The method works like this. Descartes' puts forth a skeptical hypothesis concerning a certain class of his beliefs. (He does not want to doubt each belief individually as this would be impractical.) The classes which he generates turn out to be related to particular faculties, the senses, imagination and reason. He then tries to determine what can and what cannot be doubted on the basis of his skeptical hypothesis. If there are things which cannot be doubted on a particular skeptical hypothesis, he tries to generate a stronger skeptical hypothesis which will bring into doubt those things which could not be doubted on the previous hypothesis. Eventually, the application of this method leads him to the conclusion that there are a variety of things which cannot be doubted on the strongest possible skeptical hypothesis.
Montaigne mocks reason for providing no foundation. Descartes desired to find an Archimedian point for knowledge, that is, he sought for what could be known for certain, holding that other truths could then be deduced from those known for certain. Descartes, in fact, uses the analogy of a house of knowledge. Are the senses fundamental, or imagination, or reason? Descartes proposes to tear down his house of knowledge to rebuild it. To do this he employs both the method of doubt and the method of analysis. Eventually, he finds a variety of truths which can be known for certain: "I exist." "I am a thinking thing." "I seem to see a fire before me." "I seem to see other people." These truths which can be known for certain and which are not derived from other truths, belong in the foundation of Descartes' house of knowledge.Web Master: Bill Uzgalis
Oregon State University
Last Updated: 1/96