A colleague wrote:
In both your new Rationale materials and your old Reason! lessons you distinguish between reasons and explanations. For instance, you point out that the word “because” is sometimes a reason indicator, other times an explanation indicator. I was wondering why, pedagogically, you make a point of distinguishing between arguments and explanations. You seem to want the students to focus primarily on the former and not the latter, but I anticipate that my students will find this confusing. I was wondering why, as a pedagogical matter, you point out this distinction to your students, and how you explain it to them.
My reply, such as it was:
I think that in the larger world of critical thinking, students should understand evidential reasons, and what makes them strong, and explanatory reasons, and when explanations are good ones. However when we are focusing on the former, the latter tends to muddy the waters.
Deanna Kuhn, in her classic The Skills of Argument, provides weighty evidence that a very large proportion of people have a seriously deficient grasp of the basic skills of reasoning and argument, and she diagnoses the problem as due in part to a poor grip on what a (evidential) reason is, i.e., what evidence consists in. Part of understanding this notion of an evidential relationship is understanding that sometimes, when we say things like the reason for X is Y, we’re not using Y to convince somebody that X is true, i.e., we’re using it to explain X rather than as evidence for X, which may already be uncontroversial.
There is now a considerable psychological literature on (evidential) reasons versus explanations. My take on this, which I think is broadly consistent with the literature, is that (causal) explanations come first. Our three-year-old seems to be getting a grasp of causal relations and answering “why” questions in terms of causal narratives, but she’s a long way from understanding the notion of evidence. The latter is a more sophisticated intellectual operation, one which only with considerable maturity is separated from explanations. A problem we face as university teachers is that our students haven’t fully made this transition; they are still foggy about the difference, which means they are foggy about the notion of evidence, which means they haven’t yet mastered the most fundamental concept in reasoning and argumentation.
You’ll notice that in Rationale, the second or “Reasoning” mode uses “because/but” language. This is ambiguous between explanations and evidential reasons. In the designing the software we were quite deliberately “allowing” that ambiguity, since it helps people who aren’t yet clear on the distinction become comfortable with structured reasoning on their own terms. As they progress to proper use of “Analysis” mode, with its language more weighted to the evidential (“supports”), they should be becoming more clear about what an evidential relationship consists in, not by being lectured on the topic (though that might sometimes help) but by dealing with examples in a scaffolded way.
By the way, Deanna Kuhn has an interesting piece on peoples’ ability to identify causal relationships in the current edition of Scientific American Mind.

Logic and Critical Thinking texts often make a big deal of the explanation/argument distinction, but it seems to me that it is so slippery and relative that it’s not worth much. The way it’s explained (! – or is it argued for?) is that in an explanation the “conclusion” is taken as true and not in need of “proof,” whereas in argument the conclusion is open to at least some doubt and is in need of evidential support. But whether a claim needs evidentiary support varies widely (or wildly) from person to person and context to context. Consider some claims: Cholera is caused by a micro-organism. There is an omnipotent and omnibenevolent God. The sun does not revolve around the earth. Stem cell research should be outlawed. The earth is more than 6000 years old. Astronauts have walked on the moon.
Do such claims call for explanation or for argumentative support? Seems to me that for these, and a host of other claims, in fact for almost any claim at all, it depends – on who, when, etc. In about 1870 the cholera claim was sorely in need of proof, but not today. For the astronaut claim: For those who watched Armstrong and Aldrin in (almost) real time on TV in 1969, it is silly to think there’s any need for proof of it today; yet Austhink tutorials feature an argument (not explanation?) example to show that it really happened. And so on and so forth.
So, I suppose I’ve presented – no, suggested – an argument for the dubious usefulness of the argument/explanation distinction. Or maybe there are other ways to elaborate (explain? argue for?) the distinction, of which I am unaware.
Frank W