Master of Arts
Date of Defense
Berit Brogaard, Ph.D.
Recently some philosophers, in particular J. C. Beall and Greg Restall, have defended a view they refer to as ‘logical pluralism’. This is the position that there are, in fact, several equally good but distinct logical systems according to which different arguments come out valid and invalid. No one system, they claim, is any more ‘correct’ than any other. I will have several criticisms of this view. I first argue that the phenomena of logical recapture causes problems for the pluralist. Somewhat roughly a logic is recaptured if, though all its argument forms were not valid in the full language, a restriction on the formulas of the language can render all those argument forms valid. I argue that once we recognize that this is possible the pluralist will require further argument if she is to contend that her account of the validity of the logic in question is superior to the logician who embraces recapture. My second criticism casts doubt on Beall and Restall’s view that any time one specifies a set of truth conditions one has established a type of case in which claims may be true as well as a corresponding type of necessity. I will also make some methodological points about how to decide whether logical pluralism is true and which logic or logics are correct. And finally I will concede that a form of logical pluralism slightly different from the one endorsed by Beall and Restall may indeed be true. But ultimately I will have to leave the question of whether this alternative is indeed a legitimate form of logical pluralism to be settled on another occasion.
Pruitt, David, "Evaluating Logical Pluralism" (2009). Theses. 214.