OK, so you’ve built a strong argument following the Toulmin model. You start with a clear and robust claim, then follow that with some evidence or data that supports the claim, and continue with a strong line of reasoning that connects the evidence to your assertion. That’s great, but is your listener (or reader) convinced?
Hopefully – but maybe not! A skeptical listener may already be thinking of possible holes in your argument, or wondering if what you’re claiming is really true in all cases. As such, it’s important that you address this potential skepticism concerning the veracity of your arguments.
There are two primary ways to do this identified by Stephen Toulmin, the first of which is to provide a qualifier to your argument, sometimes also known as adding modality to your argument.
Qualifying your arguments means that you are being honest and open about the particular limits of the argument you are making. This allows your claims to be seen as more credible and having a nuanced understanding of the issue about which you are speaking.
Most claims are not, or should not be, absolute. For example, it is reasonable to claim that excessive consumption of junk food can lead to obesity, and there’s tons of evidence that you could find to support this assertion in a well constructed Toulmin argument. But if, in a debate on banning junk food in schools, you simply claimed “eating junk food causes obesity”, you might be vulnerable to rebuttals showing that people who eat junk food only occasionally, and balance it out with healthy levels of exercise, don’t become fat at all.
As such, it would be wiser to add a qualifier in the Toulmin model, such as “often” or make it clear that “junk food is a leading cause of obesity”. This would go a long way toward persuading the audience to the truth of your position.
Why? Because the qualifier shows that you are serious about your argument. Rather than overclaiming, or making overblown statements that damage your credibility, a qualifier makes it clear that you have a nuanced understanding of the topic and you’re trying to persuade the listener rather than simply trying to bulldoze all opposition with bombastic rhetoric.
Let’s look at another example of a Toulmin qualifier. Take the motion “TH supports censorship of offensive material online”. Opposition might want to argue that freedom of speech is an important value that should be protected, and they might claim that censoring offensive material is a slippery slope that will lead to the suppression of dissenting views.
All fine and fair enough, but Opp need to be careful. If they say in their speech “material on the internet should never be censored” they are walking into trouble. Does this extend to outright hate speech and speech that incites racist violence? The sale of illegal drugs online? Child pornography, or sites that encourage terrorism?
Now, it’s possible to argue that this kind of online material shouldn’t be censored either, but that might not be what the opposition wants to defend. So, it might be better for them to insert a qualifier into their argument. So, if they state “censorship of offensive material online is almost always wrong”, they leave themselves a bit of leeway to exclude some of the worst stuff from the debate, and are less vulnerable to a couple of good counter examples from the other team damaging their case. They will still need to carefully explain which exceptions they support, and maybe give some criteria for what can still be censored on their side of the debate – but at least they are not defending a difficult, absolutist position.
It may seem counterintuitive, but qualifiers add strength to a Toulmin argument by answering potential questions our audience may have, and acknowledging that our logic has a limit - making our case more persuasive.