Rigorous definitions of logic—the various systems of formal logic—do not fully define reason. They are more like particular schemes that formalize and idealize

Rigorous definitions of logic—the various systems of formal logic—do not fully define reason. They are more like particular schemes that formalize and idealize some aspects of reasoning. Those systems are derived from reasoning, using reasoning, in accordance with reason, but they are not reasoning itself, unless you want to claim that the process of inventing or refining formal logics is itself unreasonable. It's impossible to fully define a foundational concept like rationality. This concept has been used as an example of an "essentially contested concept" whose "proper use… inevitably involves endless disputes."