3.6: Beginning to Evaluate Arguments (2024)

Before I said that we use argument mapping to understand an argument before we do any evaluation of those arguments as good or bad arguments, valid or invalid, cogent or uncogent, sound or unsound, and so on.

But the process of identifying hidden assumptions is in itself a sort of evaluative process: we must identify the need in the argument for another claim to be true—we have to declare that an argument is incomplete and therefore faulty before we can talk about the argument needing an extra premise.

So if we’ve already done a bit of evaluating of arguments in identifying hidden premises, perhaps those tools that we gained when we were identifying hidden assumptions will help us in trying to evaluate an argument as a good or bad argument. Let’s explore how helpful those tools are.

Recall that the central idea in the process of identifying hidden assumptions is the idea that a good, complete argument has a series of topics or terms that are linked together in the right way. This is a really informal and incomplete version of what you might learn if you learn Categorical or Aristotelian Logic. That’s the study of how categories or terms must be linked for an argument to be deductively valid.

Let’s look at how this informal idea can help us determine whether we’ve got a good or bad argument. Here’s an example to consider—it’s something you might see on social media and in the wording that one might actually find there:

If you don’t want an abortion, don’t have one.

[Implied conclusion: Abortion should remain legal and available].

Hopefully it’s relatively clear that this argument needs a tune up—not because it is wrong-headed (it might not be) or because its conclusion is wrong (it might be true), but because it’s unclear what the actual argument is: what are the premises and how do they support the conclusion?

First, we should try to interpret the argument in a way that makes the process of identifying topics easier. This process is already a bit evaluative in that we are interpreting the argument charitably: we’re trying to understand the most rational version of the argument without changing its essential content. Maybe something like:

Abortion rights aren’t abortion mandates,

so there’s no reason to oppose abortion rights.

Making abortion legal doesn’t mean requiring (mandating) anyone to have an abortion. This is already starting to look more complete, and it’s already beginning to look like a serious philosophical argument. We’ve taken it out of the format of a slogan and interpreted it as an argument.

The next step is to identify the topics being discussed:

a. Abortion rights laws

b. Abortion mandates

c. Reason to oppose things

Once we’ve identified these terms, we can think about the argument in terms of a series of propositions which connect them together.

1. Abortion Rights laws aren’t abortion mandates

[Links (a) to (b)]

2. So, There’s no reason to oppose abortion rights

[Links (c) to (a)]

We’ve got some of the tools now to recognize that there’s a missing premise here. Can you find it?

Ummm....There’s no link between Reason to oppose things and Abortion mandates, so the inference has a gap in it.

Right-o! Good work. We’ve linked a to b, and a to c, but not b to c. This is why the argument feels a bit gappy and incomplete. What, then, might our hidden premise be? We need to link “Abortion mandates” with “reason to oppose things.” Any ideas?

Yeah. Why not something like “There’s no reason to oppose abortion mandates.”

Well...not quite. That’s a pretty clearly false, statement right? Lots of people want to have children and lots of other people are morally opposed to abortions, so it makes little sense to say there’s no reason to oppose mandating everyone has an abortion, right?

Oh...yeah. What about “If something isn’t a mandate, then there’s no reason to oppose it.”

Now we’re talking! That’s a really general claim: it applies to everything (or at least every public policy or law) that isn’t a mandate. So maybe we’d want something more restrictive. Nevertheless, this is a good start. So here’s our complete argument:

1. Abortion rights laws aren’t abortion mandates

[Links (a) to (b)]

1a. If something isn’t a mandate, then there’s no reason to oppose it

[Links (b) to (c)]

2. So, There’s no reason to oppose abortion rights laws

[Links (c) to (a)]

This process is tricky and interpretive. When we get to Aristotelian Logic, we’ll cover some tools that make this a more strict and formalized process. For now, though, we’re sticking with intuitively understanding arguments and how they hang together. This is an incredibly valuable skill in all aspects of life: when is an inference making an implicit assumption? People make loads of implicit assumptions all of the time.

Okay, so the goal in this section was to start to evaluate arguments using some of the tools we’ve picked up so far. Here’s how this might go:

The first claim in this argument is that Abortion rights aren’t abortion mandates. This is clearly true. No law or policy securing abortion rights (within the realm of reasonable laws) would require that people have abortions. So there’s no problem with the first claim.

The second (hidden) claim in the argument is that If something isn’t a mandate, then there’s no reason to oppose it. This, as I said before, is very broad. It seems easy to come up with a counterexample. In this case, a counterexample would be something that isn’t a mandate, but which we would have reason to oppose. Can you think of a possible law that doesn’t put a requirement on citizens, but nevertheless is a law we’d want to oppose?

I can think of thousands. A law allowing murder. A law allowing ritual human sacrifice. A piece of legislation requesting that the President strongly consider nuking the moon....the list goes on.

So this seems like a bad principle: one shouldn’t be opposed to something that doesn’t bring a mandate with it. In other words: if it doesn’t interfere with you, then leave it alone. That’s not how a civil society, works though. We take an interest in each other’s lives for the sake of having a healthy society and protecting one another.

As I said a few paragraphs back: this hidden premise we inserted completes the argument fairly directly, but might be too general. More general than we need, in fact. We might consider something more specific like “If a law doesn’t require people to do something immoral, then there’s no reason to oppose it.” But that is refuted by the same counterexamples I listed above. We could try over and over to find more specific premises to complete the argument, but honestly at some point we have to admit that the argument as we’ve reconstructed it probably rests on a false general premise.

So in reconstructing this argument and identifying what hidden premise it rests on, we have set ourselves up to evaluate whether or not this is a good argument. You might disagree, but this seems like a bad argument for abortion rights. Best to go looking elsewhere for good arguments for abortion rights (they’re out there! Philosophers like Judith Jarvis Thomson, Mary Anne Warren, and Rosalind Hursthouse have interesting arguments indeed).