I've spend the last two years doing a reasonable amount of teaching.
I suppose that every teacher wonders whether the students are really "understanding" what we teach. This begs the question of what we mean by understanding.
One effect of doing a lot of teaching, has been that I have found that I did not understand some things that I thought I did understand. A particular example is Principal Components Analysis (PCA). I think I do understand it now, but I did not before. I have taught something about PCA in the past, and I think I was saying things that were true, but I didn't know why they were true.
What had happened was that I had heard other people that I trust say these things about PCA. I heard the same thing a few times from a few different people, and I added what they said to the store of things I "knew".
In my case, I think I was using what Perkins, Allen and Hafner call "makes-sense epistemology" (1). Someone using makes-sense epistemology is not reasoning or criticizing what they have heard. They are not asking "could that be wrong?". Their criterion for accepting an argument is that the argument feels right or makes sense.
Naive reasoners might be said to have a "makes-sense epistemology." Of course this does not mean that they have an explicit philosophy about what grounds are necessary for belief. But it does mean something in terms of the manifested behavior: such reasoners act as though the test of truth is that a proposition makes intuitive sense, sounds right, rings true. They see no need to criticize accounts that do make sense - the intuitive feel of fit suffices.
It seems to me that teachers are often in the situation where they cannot or do not hope to teach the students why something is true, but only give them a feeling for why something might be true. When we do this, we encourage makes-sense epistemology.
Does it matter that we often function on this intuitive makes-sense level? Not if we think that most of what we are told is true. But, as Richard Feynman put it: "Science is the belief in the ignorance of experts." (2).
Address "What is Science?", presented at the fifteenth annual meeting of the National Science Teachers Association, in New York City (1966), published in The Physics Teacher, volume 7, issue 6 (1969), p. 313-320 ↩