Summary: Fogelin argues that some of our disagreements are deep: they cannot be resolved by argument, because the disagreement undercuts the very conditions that make argument possible.
So what are these conditions? Fogelin notes that we must share background beliefs and preferences in order for argument to work in a disagreement. For example, imagine a friend asks you why you chose to take a certain road. You say, “I want to pick up the fish last.” Your friend replies, “we should go to the ice cream shop last; I don’t want it to melt” (Fogelin 5). Not wanting the ice cream to melt convinces you to go to the ice cream shop last, because you and your friend share detailed knowledge of local geography, preferences for frozen ice cream and fresh fish, and the common goal of doing all the shopping in one run. None of these beliefs are mentioned in the disagreement; they provide its background. Thus, background beliefs and preferences ‘provide the framework in which reason can be marshaled’ (Fogelin 5).
We must also agree about procedures for resolving disagreements in order to use argument. Fogelin imagines a disagreement about who hit more home runs in 1998. If we don’t share a background belief that checking the record books is the right way to search for evidence, then offering evidence will not move our disagreement forward (Fogelin 6).
A tool only works properly when used in normal contexts: if you remove a boat from water, then its parts can work just fine, but it will not perform its function (transporting people). That is because boats only work in water. Likewise, giving reasons will only work when used in normal contexts. The normal context of using argument in disagreement is when we share 1) a broad network of background beliefs and preferences, and 2) procedures for finding evidence. Like the boat, if we use argument outside of this context, then it will no longer work.
Deep disagreements involve doing exactly that. Deep disagreement arises because two people don’t share enough broad background understanding. Consequently, each side can strengthen its argument with more evidence and more logical rigor, but doing so will not resolve the disagreement. Rational resolution becomes impossible.
Prescriptions for Better Disagreement:The idea of deep disagreements suggests first that we should stop giving arguments once we discover that we have left normal circumstances. Unfortunately, because background beliefs form a vast framework, we can’t just isolate one difference in background belief. Instead, we need to develop strategies to share the framework that another uses to make sense of reason giving. While we can’t capture framework beliefs in single sentences, we may be able to diagnose how differences in framework make a difference in two people’s perception of how the other’s argument works. In this way, argument diagnosis, may help us reveal framework differences and appreciate the limits of argument.
Disagreement Compendium Entry for Robert Fogelin, “The Logic of Deep Disagreement,” Informal Logic, vol. 25, no. 1 (2005): p. 3–11.