Faithful readers of this blog will probably know that one of my readers, Jeff, has been criticizing my position that testimony can be a properly basic source of justified belief and knowledge (absent defeaters to the truth of the testimony). On Jeff’s view, testimony is always non-basic and is only rationally assented to based on corroborating evidence.
Jeff’s position prompted me to press him on which sources of belief can be properly basic and which are non-basic. He finally provided the following summary of his criterion of proper basicality which I’ll call Jeff’s criterion:
Jeff’s criterion (Jc): “If we have no option but simply to assume the deliverances of a source of knowledge (eg, sensory perception under normal circumstances, rational intuition), then we can accept those deliverances non-evidentially. Otherwise, we assess sources of knowledge evidentially (eg, testimony).”
I take it that Jeff wants us to believe Jc. However, a person cannot rationally believe Jc as a properly basic belief since it is clearly not among those beliefs that “we have no option but simply to assume”. Rather, it is contentious epistemological thesis. This means that if we are to be rational in assenting to Jc, Jeff will have to demonstrate how Jc is evidentially derived from beliefs that are properly basic. Thus far he has declined to provide an account of which sources of belief he accepts as properly basic, though he has specifically identified rational intuition and sense perception. So if Jeff is justified in believing Jc he should be able to demonstrate how it is derived from properly basic beliefs of rational intuition and/or sense perception.
I await with great anticipation Jeff’s defense of Jc.