Reasonable argument

From Tech Central Station: Arnold Kling looks at two types of argument that might be brought against any proposition, which he calls type C and type M.

For example, suppose I were to say, "We should abolish the minimum wage. That would increase employment and enable more people to climb out of poverty." There are two types of arguments you might make in response. I call these Type C and Type M. A hypothetical example of a Type C argument would be, "Well, Arnold, studies actually show that the minimum wage does not cost jobs. If you read the work of Krueger and Card, you would see that the minimum wage probably reduces poverty." A hypothetical example of a Type M argument would be, "People who want to get rid of the minimum wage are just trying to help the corporate plutocrats."

What is the difference between these two types of argument?

Type C arguments are about the consequences of policies. Type M arguments are about the alleged motives of individuals who advocate policies.

A practical difference between these two types of argument is that type C arguments involve data, evidence, and counter-evidence. Sooner or later, at least in principle, it's possible to show that one side or the other is wrong, and that the person on the wrong side of the argument will change his mind. A type M argument, denigrating the motives of the person stating a proposition, attacks the right of a person to even state the case.

Kling gives examples of type M arguments dealing with tax cuts, school vouchers, and the war in Iraq.

C.S. Lewis came up with a name for type M arguments: Bulverism.

Bulverism is a kind of ad hominem argument, which in turn is a kind of material fallacy of relevance. In Bulverism, you attack the motives of a person offering an argument, and argue that those motives render the argument false or illegitimate. (For example: "Republicans favor tax cuts because they're greedy and want to cause suffering among the poor.") Bulverism is closely related to the complex question, in which an unstated proposition is assumed as the foundation for another statement or question, such as: "Why are you so greedy and so mean to poor people?" In this example, the overt question, asking about the reasons for the person's motives, assumes the motives exist. If these motives have been established in the first place, that's a reasonable question. If they haven't, it's not.

Bulverism is a fallacy of relevance because the motives of someone arguing for some policy have no necessary bearing on the effects of that policy. It's quite possible that someone with base motives (such as a desire for worldly fame) may do something that has a good result (such as endowing a hospital in his name). On the other hand, the paving material for the road to hell is notorious.

One consequence is to lower the level of political discourse in general. You have a lot of influence with those who sympathize with your views. When they see you adopt type M arguments, they do the same. Conversely, many of your opponents are stooping to your level. I see type M arguments raised by many of your enemies on the Right. As horse manure draws flies, your columns generate opposition that is vindictive and uninformed. Another consequence is to lower the prestige and impact of economists. We are trained to make type C arguments. Instead, you are teaching by example that making speculative assessments of one's opponent's motives is more important than thinking through the consequences of policy options. If everyone were to use such speculative assessments as the basis for forming their opinions, then there would be no room for economics in public policy discussions.