Digital Companion to C. S. Peirce
1902 | Minute Logic: Chapter III. The Simplest Mathematics | CP 4.240
Mathematical logic is formal logic. Formal logic, however developed, is mathematics. Formal logic, however, is by no means the whole of logic, or even its principal part. It is hardly to be reckoned as a part of logic proper.
‘Formal Logic’. Term in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from http://www.commens.org/dictionary/term/formal-logic, 28.05.2023.