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Fabio Paglieri: On the unproblematic gappiness of fallacies

Colloquium lecture by Fabio Paglieri (ISTC-CNR Roma, Italy), organized by the Dept. of Theoretical Philosophy


Fallacies still figure prominently in argumentation theory, as well as in critical thinking education, in spite of the increased criticism targeted at this notion. While lists of fallacies have flourished since antiquity (ad hominem, ad ignorantiam, ad populum, secundum quid, post hoc ergo propter hoc, to mention just a few of the usual suspects), the relevance of the notion has been questioned: in contemporary argumentation theory, both scheme-based approaches and rule-based models allow for the very same scheme or rule application to be either fallacious or non-fallacious, depending on contextual factors.

This in turn puts fallacy theory into a quandary, since the notion of fallacy is either too narrow to fruitfully apply to real life cases, or so nuanced as to fail to effectively discriminate good and bad forms of reasoning. Similar concerns apply even to formal fallacies, such as denying the antecedent (DA) and affirming the consequent (AC), which have been recently reinterpreted as Bayesian ‘quick and dirty’ informational shortcuts, based on assuming that either there are no false positives, or that they are so improbable as to be negligible. This is interestingly related to Stalnaker’s interpretation of a conditional statement a → c as P(c|a), since in that case whether DA and AC are legitimate inference depends on the proximity to the actual world of the state of affairs described by the conditional. Moreover, there is growing empirical evidence that ordinary speakers are remarkably good at intuitively discriminating between legitimate and illegitimate uses of such shortcuts, so that using fallacy theory for educational purposes has been argued to be useless or even counterproductive.

In light of these developments, the last line of defense for the “fallacy buff” is to insist that all attempts at showing so called “fallacies” to be, in fact, non-fallacious rest on complementing the uttered statements with something else, be it probability distributions, similarity relations among worlds, contextual features of the dialogue, etc. Therefore, the fallacy buff would stress, fallacies remain gappy on all accounts: they cannot stand on their own, and this is the hallmark of their failure. In this paper, I discuss this line of argument against the background of the relevant literature, to show that:

  1. gappiness per se cannot be considered a capital sin, lest we throw away the baby of enthymematic reasoning with the bathwater of alleged fallacies;
  2. what would make the gappiness of fallacies “bad” are the same criteria that would disqualify as illegitimate any other form of enthymematic reasoning – namely, the fact that what is left implicit is either controversial or unclear to one of the parties;
  3. thus whether the gappiness of fallacies is problematic or not ultimately rests on an empirical question, albeit one with profound implications for the philosophy of reasoning and language;
  4. on balance, extant evidence support the claim that most alleged fallacies are gappy in unproblematic ways, thus vindicating a “greener approach” to logic.
When & where?

Wednesday 30 September 2015, 3.15-5 pm
Faculty of Philosophy, room Omega

Last modified:31 August 2015 4.41 p.m.