According to the standard liberal egalitarian approach, religious exemptions from generally applicable laws can be justified on the grounds of equal respect for each citizen’s conscience. I contend that claims of conscience cannot justify demands for exemptions, since they do not meet even the most inclusive standards of public justification. Arguments of the form ‘My conscience says so’ do not explicate the rationale behind the practices that the claimants seek to protect. Therefore, such arguments do not constitute even pro tanto (...) reasons for exemptions. Rather, they are what Francis Bacon called idola fori – ‘idols of the marketplace’– conventional justifications that are deemed rational and even self- evident, while in fact they are not. (shrink)