Practical reason (n.) is a call for formal 'duty' over and above desire-based practical reasoning.
Definition.com
Definition.com
Practical reason (n.) is innate and not derived from experience.
Definition.com
Practical reason (n.) inverts speculative reason: here the pure use is immanent and the empirically conditioned use, presuming to be sole ruler, is the transcendent one.
Definition.com
Practical reason (n.) has a voice that makes even the boldest offender tremble and hide from his own sight.
Definition.com
Practical reason (n.) cognizes God, freedom and immortality: it tells us that their objects exist without telling us how or what they are; speculation gains nothing, reason gains everything it needs to act.