L. Jaffro (2010). Rétorsion du sens commun et possibilité du scepticisme. Contre Reid. In M. Cohen-Halimi and H. L’Heuillet, Comment peut-on être sceptique ?. Paris: Honoré Champion, 93-116. https://halshs.archives-ouvertes.fr/halshs-00264778v2/document
This essays aims at assessing the ad hominem argument from common sense used by Thomas Reid, particularly against David Hume, and claims that the argument does not prove that scepticism is impossible. Attention is drawn to two difficulties in Reid’s attack against the sceptic. The first difficulty lies in Reid’s joint use of two different conceptions of common sense: an intuitionist conception that equates common sense with a set of primitive intuitions and ‘first principles’ evident by themselves; a pragmatic conception that sees in common sense a sensitivity to norms, most often implicit, of practice and communication. In the pragmatic conception, a second difficulty lies in the tacit identification between two dialectical arguments that can be called, following Perelman’s ‘new rhetoric’, the argument from direct inconsistency and the pragmatic argument (pointing out indirect inconsistency). The last section draws on John Mackie’s logical analysis of various forms of alleged self-refutation to criticise the ad hominem argument against the sceptic.