Why did Aristotle call logic a tool rather than a theoretical science?

Aristotle classified logic as a tool rather than a theoretical science because he reserved the term "science" for specific disciplines such as physics, mathematics, and metaphysics, as detailed in his Posterior Analytics.12

For Aristotle, logic served as a universal instrument or method used by all sciences to conduct rigorous reasoning and demonstration. His collection of logical writings, known as the Organon (meaning "tool"), reflects this functional role. While he did not categorize logic as a theoretical science, he maintained that it was a highly rigorous discipline. By developing a system of rules and strategies—most notably the syllogism—he provided a framework for navigating logical consequences, which he viewed as essential for the pursuit of knowledge across all fields of inquiry.12