Holistic Conditionalization and Underminable Perceptual Learning

Seeing a red hat can (i) increase my credence in the hat is red, and (ii) introduce a negative dependence between that proposition and potential undermining defeaters such as the light is red. The rigidity of Jeffrey Conditionalization makes this awkward, as rigidity preserves independence. The picture is less awkward given ‘Holistic Conditionalization’, or so it is claimed. I defend Jeffrey Conditionalization's consistency with underminable perceptual learning and its superiority to Holistic Conditionalization, arguing that the latter is merely a special case of the former, is itself rigid, and is committed to implausible accounts of perceptual confirmation and of undermining defeat.