Most philosophical views are not completely incorrect. They contain at least partial truths. The key to making philosophical progress is to be able to distinguish the partial truth from mistaken or unhelpful parts of the view. To liberate the grain from the chaff.
One way to do that is to compare opposing views, a thesis and an antithesis, looking at their strengths and their weaknesses.
You come up with strengths and weaknesses of both the thesis and the antithesis. When you have done this, you might find yourself in a position to (5) construct a third view, the synthesis, which combines the strengths of both positions without their weaknesses.
Here's how we might do that with dogmatism (thesis) and skepticism (antithesis).
1. Strength of dogmatism. It says we have to just assume some things and not question them. This makes sense because if we had to prove everything we would never be able to act. You'd need a reason to act; then a reason for that reason; then yet another reason for that reason, without end.
2. Weakness of dogmatism. People who have beliefs that cannot be questioned will act in accordance with those beliefs. It is as if they are controlled by those beliefs (which they probably got from some authority figure or supposedly infallible book). You could be seriously misled. There are examples of people in racist societies never questioning the myth that black people are inferior and people in a sexist society never questioning the myth that females are inferior. If there are some beliefs that you cannot question, you may be a part of an unjust system, you may be guilty of oppressing others without realizing that you are doing anything wrong.
3. Strength of skepticism. The skeptic, who holds that we should doubt everything, enables us to avoid the kind of mistake criticized in the preceding paragraph. A thorough skeptic would never say that he knows that females are inferior or that blacks are inferior.
4. Weakness of skepticism. Skepticism not only doubts one side of dispute. It also doubts the other side as well. It suspends judgment. The skeptic on the race question is no help to the struggle against racism because he cannot commit himself to the basic equality of the races or to the fact that discrimination on racial lines is wrong.
5. Synthesis. Part of the problem here is that skepticism is confusing doubt as a part of inquiry with total and lasting doubt. Dogmatism, on the other hand, seems to be assuming that if we do not doubt an idea now, we have to accept it always without questioning it.
The solution is to realize that it is not necessary to doubt all ideas at one time. We can hold some ideas as basic and use them to check whether other ideas are true or not. The chemist who tests whether a given substance is acidic assumes that the techniques that worked in the past to determine what is acidic continue to work. In other words, she is dogmatic about the standard tests while she is skeptical about whether something is acidic.
Ideas that are accepted dogmatically at one time in one context may still be questioned at another time in another context. In her more philosophical moments, the scientist may wonder whether the normal laws of nature (which enable her to conduct experiments) are always actually the same, or whether they might change, for example, as the universe expands.
Thus, the dogmatist is right that some ideas must be assumed true in order for action or inquiry to go on. But no idea is permanently immune to being questioned or doubted and tested. However, the goal of doubting and questioning is not what the skeptics say, a suspension of belief either way regarding disputed questions. The goal is more reliable belief, greater knowledge.
Thus the synthesis has led us to epistemological optimism--the view that we can gain greater certainty and knowledge about at least some ideas. We do not need to adopt the view that there are sacrosanct ideas that should never be doubted.