For the ease of expression, I will speak about "truth" and "falsity," though I do not think there is a simple, objective “truth”—or at least logic does not easily lead us to such a thing. As I said in my previous post, however, it seems to me intuitively the case that some things are obviously true and some are obviously false.
For example, I drank some water just after starting this post. I think that is absolutely true. And it is absolutely false that I drank some whiskey just after starting this post. I think that there are many things in the world that can be said to be true or false and it’s useful to be able to distinguish the two.
Ultimately, I think this is the purpose of research. Even those who reject the idea of an absolute truth are, at the least, looking for ideas that can be used by many, not just a few.
As I have said in previous posts, knowing the truth is important. To buy something at a store, I need to know where the store is. To buy the right thing, I need to know what my needs are. To make an effective plan for dealing with research, I need to know how research works. And so on, and so forth.
The idealized scientist/researcher challenges accepted ideas. For example, Darwin or Galileo. But which ideas do we challenge? Which ideas do we accept?
Often, one reason to accept or challenge an idea is because of the speaker. But the identity of the speaker is no guarantee of the truth or falsity of a given claim. The ad hominem argument—the argument “to the man/person” (I think is the translation of the Latin)—attempts to build a claim about the truth of a statement based on identity of the speaker. This is logically a fallacy: the truth of a statement does not depend on the speaker.
There are times when this really bothers me. In political arguments, the ad hominem fallacy is infuriating and generally misplaced. To say that research is suspect because the researcher is affiliated with a particular political party is, quite frankly, asinine. If you believe that research is flawed, you should be able to do better than “I don’t trust the person who did it.”
Even in the case of a proven serial liar, there is a good chance that the next claim will be true. The identity of the speaker does not guarantee the truth/falsity. Ideally, a critical thinker—including scholars/researchers/scientists—will check an idea on its own merits.
But practically speaking, we can’t do that. We can’t check everything. And so we rely on trusted sources. Hopefully we have a good knowledge of the ideas we are using, and understand their strengths, weaknesses and controversies; hopefully we do not just accept/reject ideas because of the speaker, but practically speaking, it’s often effective to do just that.
From the perspective of a writer, it’s a crucial and invaluable tactic: we cite some scholar or philosopher, and that is the terminus of a line of exploration. Again, the scholar ideally has theoretical reasons for the choice of a given idea, and does not choose the idea on the basis of the speaker. But in the battle to keep a presentation to a reasonable length, calling on well-known names can be an invaluable tool in reaching and convincing an audience, while avoiding the morass of theoretical debates that surround most important ideas.