Attacking Evidence

We have been talking about advocacy and, as one good friend and past student remarked to me last week, “Just because it isn’t the preferred way to communicate doesn’t mean you shouldn’t teach it.” And of course, she is right. We need to know how deal with things as they come to us. This week, as promised, I’ll cover how you attack a case. Next week, we’ll talk a bit about how to convert Advocacy discussions into Collaborative discussions (which IS the preferred way to communicate).


First, recall that there are three parts to the SPIRAL model; 1) the claim, 2) the Evidence to support the claim and, 3) the Inference that connects the evidence to the claim. The best way to attack advocacy positions is to attack either the evidence presented, or the inference.

There are three kinds of evidence; 1) the presenter’s credibility, 2) Objective evidence (evidence that can be independently examined and reviewed) and, 3) Social Knowledge (common knowledge, stipulation, or other things that “we all know” and “go without saying”). Effective attacks can be made against any of these.

First, we can attack the presenter’s credibility. The first run should NOT be personal. We can for instance, raise doubt as to whether the presenter really has any expertise in the subject at hand, or whether they actually have any first hand access to information, or if they are simply speculating. If we choose, we can make it more personal and describe their sketchy track record of being right on the subject, or their background and training is too lightweight for them really to grasp the subject under discussion thoroughly.

You can attack Objective evidence in several ways. First, if it is statistical, it is usually easy to show that it was not gathered properly. You can find more on that here. Other kinds of objective evidence can be dismissed if you can show that the evidence could also be attributed to something else. For instance, I was once in a discussion in which an opponent mentioned that “children with low birth weights tend not to attend college”. I pointed out that there are many of reasons that certain groups tend not to attend college. One of those groups is the poor, which is also a pretty good reason for having low birth rates. I finished by saying that if they had done any research at all they would have seen how incomplete their logic was and never had made the statement. So, even though they were correct, it appeared that they hadn’t thought out their position.

Common knowledge is easy to disrupt too. You can point out other things that are supposedly common knowledge that are untrue (cashew nuts are not nuts, for instance), or things that have ONCE been common knowledge (the Earth as the center of the Universe, for instance) and describe that just because we accept certain things as true today, doesn’t make them true. Finally you can point out counterexamples in order to dismiss ideas. For instance, if someone points out a certain team is a great team and claims it is because the individuals on it possess great individual talent, you can point out teams that contain no stellar individuals but still function well as a team, OR you could point out teams populated by superstars that don’t live up to potential of the individuals because they don’t work as a team. In other words, it is usually easy to find exceptions to generalizations and most common knowledge is based on generalization.

Next time, we’ll attack a position based on inferences.


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