Title: "What is it to know a logic? To understand the discourse it

specifies perhaps?"

Although there has been more than a century of experimental psychology

done on tasks which experimenters suppose to be understood by their

subjects as classical logical tasks, there are good arguments that

many of the subjects interpret these tasks in a nonmonotonic logic

(Stenning and van Lambalgen 2006). So what do subjects know of

classical logic? This talk proposes that the answer must lie in what

they understand about the discourse classical logic specifies:

paradigmatically, `adversarial' argument.

An exploratory experiment which embeds categorial syllogisms in a

discourse of dispute produces data which is encouraging of this

approach. Subjects do produce performance nearer to classical

reasoning, and the control conditions produce data persuasive that

the conventional task is often interpreted nonmonotonically.

If these results are sustained, where should we look for the

psychological and historical origins of our understanding of classical

logic? We suggest in our affective understandings of dispute.

Reference: Stenning, K and van Lambalgen M. (2006) Human Reasoning and

Cognitive Science. MIT Press.