How should those who value reasonable pluralism navigate ethical and epistemological challenges related to speech and inquiry in higher education? We propose the ethical pursuit of public knowledge as a guiding vision for public colleges and universities with the understanding that other institutions will serve different purposes. The ethical criterion of mutuality calls for engagement across difference and reciprocal recognition of others' basic equality and liberty. To maintain epistemic legitimacy, knowledge-production processes in these institutions should elevate ideas warranted by public reasons that have withstood rigorous critical scrutiny above those that have not. Some forms of speech--including the expression of extremist views on both the Right and the Left--will prove unreasonable and incompatible with the guiding vision and should therefore be marginalized (but not necessarily suppressed) within these institutions.