Science advice for policy: enhancing the legitimacy of non-epistemic value judgments through proportionality analysis

Science advice bodies increasingly shape public policy. Yet, their analyses and recommendations routinely involve non-epistemic value judgments that sit uneasily with ideals of democracy and separation of powers. We argue that in liberal constitutional democracies the political legitimacy of such judgments can be enhanced by integrating structured proportionality analysis into the workflow of policy-recommending advisory bodies. This deliberative procedure – first developed by constitutional courts – brings attention to policies’ impact on protected rights and amounts to a multi-pronged scrutiny of the justifiability of a policy which infringe on rights. We show, first, that existing guidelines for science advice bodies nationally and in international organizations implicitly acknowledge non-epistemic judgments but under-specify how to deal with them. Second, recent philosophy of science rightly foregrounds the democratic scrutiny of values (and so representation, alignment, and participation) but underemphasizes rights-based constraints. Our proposal reorients advisory practice toward rights-sensitive, deliberative justification that science advice bodies can apply ex ante—where these bodies often possess superior expertise on relevant aspects such as the suitability and necessity of a policy. Embedding proportionality analysis both mid-stream (to shape option generation) and in public justifications (to enable contestation and deliberation across branches and publics) improves transparency, mitigates overreach, and aligns advice with the rule-of-law and rights commitments of liberal democracies. The final part discusses scope conditions, institutional implications and limitations of our proposal. Structured proportionality analysis does not guarantee optimal outcomes, but supplies a stable, recognized method to discipline non-epistemic judgments and thereby enhance the legitimacy of science-based policy advice.