If we would guide by the light of reason, we must let our minds be bold.

The line links rational inquiry with intellectual courage: reason is not merely a cool, cautious faculty but one that requires boldness to follow evidence where it leads, to question inherited assumptions, and to accept unsettling conclusions. In Brandeis’s orbit—law, public policy, and democratic governance—the sentiment fits an ethos of independent judgment: reforms and just decisions often demand the willingness to think beyond convention and to resist pressures of authority, fashion, or fear. The quote thus frames “reason” as a guiding light that only works when the mind is willing to be adventurous, open, and unafraid of dissent.