In a previous series, I claimed that knowledge varies with the science the knowledge is a part of. Since I am most interested in philosophy, I thought I would discuss some of the issues peculiar to philosophy. Before discussing such a major issue, I thought that I would survey some of the important positions.
Some philosophers have believed that philosophy gave us the highest form of knowledge. Aristotle is one of these philosophers. He believes that there is no science higher than that of philosophy. By using reason to reflect on the most general truths of the world, we can gain knowledge of the world that does not require principles from other disciplines. Philosophy does not need any other sciences in order to be understood, nor for any of its conclusions to be believed.
Other philosophers, such as Thomas Aquinas, believed that philosophy was second to theology in importance. Theology was higher because it revealed truths that were above reason but not contrary to reason. Philosophy was still the highest science that did not begin with divine revelation. It might use theological truths as a way of checking philosophical conclusions, but the conclusions did not require theological training.
After Aquinas, his position was rejected in two different ways. One set of philosophers claimed that philosophy did not give knowledge because only theology could do that. These Bible-only theologians claimed that we must begin with the Bible and end with the Bible. Philosophical knowledge cannot exist because it treats human beings as beings capable of independent reasoning. For theological reasons, they rejected this understanding. The second set of philosophers claimed that there is no difference between truths contrary to reason and truths above human reason. Either these are areas that human reason cannot understand (as the first group claimed) or these theological opinions are simply false. These two groups are the pietists (Kant) and empiricists (Hume).
The empiricists promoted natural science as the standard example of good human reasoning. But natural science can say nothing about philosophy. So philosophy was reduced to two possibilities. Either it was a system for the systematic understanding of the natural sciences or it was a system for expressing our opinions in a rational fashion. This meant that traditional dilemmas on the nature of free will, existence and universals were simply treated as nonsense. They did not fit into either of the categories. A. J. Ayer is an example of this kind of thinking.
Finally, some philosophers have treated philosophy as an examination of certain problems. It does not provide solutions to these problems, but the problems are real, significant and traditional. We can certainly learn by examining them, but no philosophers have found the solutions because no philosophers can agree on a solution.
Next, I will discuss the limits of human reasoning.