Can Public Rules Be Justified Only by Private Beliefs?

Imagine a public school restricting what every student may wear, with the only justification being that a particular religious doctrine requires it. People who share that doctrine may regard the reason as decisive, while those who do not must still obey the rule. The issue is not that religious belief must be false. It is whether public power may demand compliance from everyone using premises accepted by only some.

Rawls’s idea of public reason responds to enduring reasonable disagreement. Free and equal citizens will hold different views about religion, morality and a good life. On constitutional essentials and basic justice, political coercion should therefore be justified through values people can assess as citizens, such as liberty, equality, security and fair cooperation. Later theories extend this demand to a wider range of coercive rules. Public reason does not require unanimous actual agreement, and it is not whatever a majority happens to prefer: dissenters may still challenge the evidence, proportionality or enforcement.

Private belief may properly motivate someone to care about an issue and may enter public discussion. The further requirement is that a rule limiting others also be supported without requiring them to join a particular faith or comprehensive worldview. A clothing rule intended to address laboratory safety can be debated through testable risks and the least restrictive response. “Our doctrine says so” does not yet treat other people as co-authors of the rules imposed on them.

My judgement is that the stronger the coercion and the more basic the interest affected, the stricter the demand for public justification should be. Public reason does not guarantee a single answer, but it separates “I deeply believe this” from “we have reasons we can assess together”.

https://plato.stanford.edu/entries/public-reason/