Knowledge laundering: testimony and sensitive invariantism
The words 'taller than the average American male' express the same property at every context of use, but how tall something must be in order to have this property varies with the time and world of evaluation. In 1974, my father had this property, but now he does not, even though his own height has not changed. In the same way, sensitive invariantists claim, the word 'know' expresses the same relation at every context of use, but how good an epistemic position an agent must occupy in order to stand in this relation to a proposition depends on the agent's practical situation at the circumstances of evaluation. Thus it can be true that yesterday Sally knew that Sacramento is the capital of California, but today she does not, though her epistemic position has not changed. In this way sensitive invariantists can acknowledge a kind of variability in the epistemic standards required for knowing, without denying (as contextualists do) that 'know' expresses the same relation at every context of use.1 In this note, I will show that sensitive invariantism is incompatible with a widely held view about how knowledge is transmitted through testimony. I will not take a stand here on which of these views should be rejected.