A Decision Procedure for Evaluating Natural Language Arguments

My fellow pupae,

I think that those of you who are teaching logic and critical thinking might find this a useful addition to your arsenal of teaching resources.

There's more interesting stuff in this issue of the APA Newsletter on Teaching Philosophy.

Comments

[Marcus Arvan]

Moti: I introduce my students to something like your decision-procedure in the very first lecture in most of my undergraduate courses. However, one incredibly important thing that your decision-procedure leaves out -- and which I think is vital to spend a great deal of time on -- is how to evaluate the truth of a premise.

In my experience, students tend to think a premise is true iff it can be "proven" by science, and that any premise that fails to meet this standards is "just a matter of opinion." I've found that in order to combat this -- and so, in order to give a much more complete picture of how to evaluate arguments -- one must spend a great deal of time investigating the notion of (objective) truth.

But of course this requires going far beyond a decision-procedure, especially when we're talking about value-theoretic arguments (e.g. moral arguments). I don't mean to suggest that you're unaware of these issues. All I mean to say is that it makes it far more difficult to see how there can be a genuine decision-procedure for arguments. Such a procedure would have to involve an uncontroversial account of what *counts* as a true premise, and insofar as I don't think we have that, I think if we are to be honest with our students we have to give a more nuanced view of how to evaluate arguments.

Thoughts?

[Moti Mizrahi]

Marcus: I wish there were a decision procedure for figuring out the truth value of propositions. That would be awesome!

Seriously, though, here's what I say about this issue in the article:

The decision procedure helps students see that argument evaluation is (broadly speaking) a two-step process. First, the logical form of the argument must be evaluated, i.e., whether the premises provide deductive or inductive support for the conclusion. Second, the content of the argument must be evaluated, i.e., whether the premises are true or false. Although the first step is not necessarily temporally prior to the second, it does seem to be the case that figuring out the logical form of an argument is easier (e.g., less time-consuming) than figuring out the truth value of its premises. So, even if students cannot judge whether an argument is sound or cogent, they can still judge whether or not the conclusion would be worthy of acceptance if the premises were true.

[Marcus Arvan]

Moti: I don't think we disagree. Like I said, I do tend to teach my students more or less your decision-procedure. My worry is that just about every paper or book chapter I've ever read on basic philosophical methodology says far too little about evaluating premises. In my experience, it's probably the most important "fundamental" to teach students about -- and to get them to think deeply about before embarking on philosophy at all -- and yet papers and book chapters on basic philosophical methods tend to say very little worth mentioning about it!

[Moti Mizrahi]

Interesting! Any thoughts as to why that is the case (i.e., why there's very little discussion of evaluating premises)?

[Marcus Arvan]

Moti: my initial thoughts are these...

First, there just *aren't* any widely accepted views about what premises are legitimate to invoke in argument. Some people argue from premises they think are "plausible", others from foundational premises they believe any reasonable person will recognize as true, etc.

Second, I think this is something of a scandal. Different philosophers often have such different standards, and so rarely discuss the matter, that it's almost never really clear -- even among professional philosophers -- which standards for evaluating premises are correct. It's something that, in my view, needs a lot more discussion in our profession. It bugs me to no end when I see people invoke premises in arguments that I think no one has any legitimate business invoking (my favorite example: "Psychopaths have [normative] reasons to be moral." Asserted all the time as a premise. By my lights, no reason at *all* to believe it is actually true).