Refining Reid's principle of credulity

In my paper " Refining Reid's Principle of Credulity" I show how my two-mode theory of testimony, inspired by Thomas Reid's ideas about testimony, can account for the following features of testimony:

Our response to testimony changes over time

We all have a powerful, innate tendency to accept other people's testimony. We respond to testimony as if that response were governed by the defeasible acquisition rule: Accept others' assertions. This propensity, as Reid says, is unlimited in children, but as people grow up they learn to resist it.

People can respond to the same testimony in different ways

The factors that cause us to override the acquisition rule are learnt and there's no reason to think that everyone learns the same set. The fact of cognitive diversity also shows that not all people respond to testimony in the same way.

We are recipients of testimony before we are transmitters or originators of testimony

Michael Dummett has persuasively argued that learning your first language goes hand-in-hand with acquiring beliefs through testimony. Before somebody can make an assertion they have to know a language.

Perceptual knowledge presupposes testimonial knowledge

Perception needs to be distinguished from perceptual knowledge. We cannot help but perceive when we're conscious, but acquiring perceptual beliefs involves making a judgement about our surroundings and that requires knowing a language and that means being in possession of testimonial knowledge.

We cannot avoid acquiring false beliefs through testimony

Our natural response to testimony is to accept it. We have to learn to override the acquisition rule, but it's impossible to devise a foolproof set of overriding factors that prevent us from acquiring any false beliefs at all.

I have written many other papers on testimony and a summary of my current views on how we acquire propositional information from other people is available on this website.

© Antoni Diller (27 March 2014)


  • Antoni Diller, "Refining Reid's Principle of Credulity". This is a handout prepared to accompany a talk I gave at the "Thomas Reid: From His Time to Ours" conference on Thursday, the 25th of March 2010; it makes clear my indebtedness to Reid. The conference was held at the Universities of Aberdeen and Glasgow. A PDF version of this paper is available on this website.