Tuesday, September 6, 2011

Objections and Defeaters

What good is an objection? An objection is a counterexample or truth which, at the very least, gives doubt to a particular proposition or premise. An objection to a premise or a proposition can take one of two forms: 1. An undercutter, or 2. A defeater.

An undercutter, strictly speaking, does not mean the proposition offered originally is false. It means only to say that we have some other reason to think that the proposition might not be true; at the very least, to think the proposition is just as plausibly false as true. An example would be an argument concerning the problem of evil or suffering. Sometimes it is asserted, “a loving God would never allow this much suffering in the world.” Theists have sometimes offered the fact that we are in no epistemic position to say what any varying amounts of suffering would do to an overall goal of a loving God with respect to his creation, and thus there’s no reason to suppose this is true. This is a particularly strong undercutter, because if true, the above proposition is pure speculation, and hence not even plausibly true (at least not more so than its negation).

A defeater is such if it renders the proposition or premise false in light of the defeater’s truth. That is, a rebuttal only functions as a defeater in the case that if it is true, the proposition is not true. A good example is this: suppose I claim that I was at work on Sunday afternoon. However, you were watching ESPN’s SportsCenter and saw me at a football game in some highlights. That viewing, if one could be reasonably confident it was me, functions as a defeater for my claim that I was at work. Of course, as savvy readers will no doubt point out, if my work involved being at the football game, then the proposed defeater is not really one at all. As one can see, then, defeaters depend on knowledge of the situation. Without the knowledge that my job was being at the football game, one is entirely rational in saying he has a defeater for my earlier proposition.

What is the point? One must understand what qualifies as a proposition, undercutter, or defeater. Otherwise, he will make poor judgments in regard to the burden of proof. In a particular doctrinal debate I was involved in recently, the opponent (who is a brother in Christ) offered what was actually an attempted defeater of my proposition. We’ll say my proposition was “X did not-Y in C.” His defeater was “X did Y in C.” Obviously, if he was right, he had a defeater for my belief.

The problem was that there did not seem to be any evidence for this belief. His rejoinder was “you can’t be certain that ‘X did Y in C’ is false, so I am consistent in this belief.” Did you notice the problem? He offered no reason to accept the defeater. He simply offered it, and then when questioned treated his premise as—not a defeater—a response to a defeater! A tactic for responding to defeaters is to show that they are unwarranted, or that one is perfectly consistent in maintaining his belief, and thus there is no reason to accept the defeater. But if a defeater or undercutter is offered by one party but challenged by the other, it is incumbent upon the objector to offer reasons one should accept his defeater or undercutter.[1]

It is vitally important the defender of biblical Christianity learn both to identify these types of objections and employ them correctly in debate. She must identify them because she must be able to point out when an opponent has incorrectly used the idea of a defeater. She must employ them correctly because she does not want to use debate trickery to “win.” She should rather be interested in truth.

                [1] It’s worth noting that one may actually have a defeater for a defeater (something in virtue of which the defeater is known to be false), but in that case the defeater-defeater must be justified as well.

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