Aristotle discusses dialectic in his book Topics. He says that there are three reasons to use dialectic: for practice in arguing, to discover problems with someones beliefs and to help find the central principles of a discipline (such as biology, religion, carpentry, etc). Aristotle is correct and these reasons are still important today.
The first reason Aristotle gives is that dialectic gives us practice in arguing. Arguing is not something that is easy to do right. We often let our emotions control us when we argue, dont understand the other person properly or dont explain our position very well. The only way to become better at arguing is by practice. By practicing we will learn to argue without having these sorts of problems. We cannot avoid arguing because arguing is necessary. Since arguing is necessary, we might as do our arguing well as opposed to doing it poorly.
The second reason Aristotle gives is that dialectic helps us discover problems with other people’s beliefs. We should not accept whatever we are told. But the only way to properly determine what we should accept and what we should not accept is by using dialectic. Dialectic is the method used to find reasons for and against any belief at all. We should believe something because we have reason to think it is true. Not everything in life depends on belief directly, but such beliefs impact our lives indirectly all the time. For example, we believe that we live in a democracy. Perhaps we do not. Surely that would be important. We also believe that recycling is good for the environment. If it were not, most of us would quickly stop recycling. Some people believe that the world is flat. We know that they are wrong, but how could we show that they are wrong?
The third reason Aristotle gives is that dialectic helps us discover the central principles of a discipline. You cant really study religion or science if you don’t know what they are or how to study them. It is the same way with a skill such as carpentry. You cannot actually do carpentry if you believe that carpentry is working with plastic. Dialectic helps us to discover these central principles. By examining a discipline we can find out what it is and how to do it properly. The major reasons for doing so are many. Is intelligent design science or not? You have to know what science is to answer that question. Are public schools teaching religion? You have to know what religion is to answer that question. And these are not the only issues that require us to know what various disciplines are. There are issues to do with the relationship of the church to the state, religion to science, the right form of government, what laws should be obeyed and many others.
These three reasons give us plenty of cases in which we must use dialectics. That means that dialectic is something good. We should learn how to use it properly so that we are using good arguments, believing the truth and understanding the issues of our day properly.