“Logic is the wall that protects the city of philosophy.”
— Zeno of CitiumStoic image reported in later doxographic sources, attribution uncertain; approximate English rendering
Commentary
This metaphor, which presents logic as the defensive wall around the city of philosophy, is a familiar Stoic image, and it reflects the high value the school placed on dialectic and the theory of knowledge. The image suggests that logic guards the other parts of philosophy against error, and that the rigour of argument is necessary for the pursuit of virtue. A. A. Long and D. N. Sedley, in The Hellenistic Philosophers, discuss the Stoic logic as a field of unusual technical sophistication, and they note that its defenders regarded it as indispensable. Malcolm Schofield has drawn attention to the civic imagery of the Stoics, in which philosophy is treated as a polis with its own institutions and protections. Brad Inwood argues that the Stoics took logic seriously because it governed assent, which in turn governed right action. Julia Annas notes that the image of walls and cities is traditional, and that its attribution to Zeno personally is not secure. The English is a paraphrase of a doxographic image, and it should not be quoted as a verified saying without checking the sources.
Commentary
This metaphor, which presents logic as the defensive wall around the city of philosophy, is a familiar Stoic image, and it reflects the high value the school placed on dialectic and the theory of knowledge. The image suggests that logic guards the other parts of philosophy against error, and that the rigour of argument is necessary for the pursuit of virtue. A. A. Long and D. N. Sedley, in The Hellenistic Philosophers, discuss the Stoic logic as a field of unusual technical sophistication, and they note that its defenders regarded it as indispensable. Malcolm Schofield has drawn attention to the civic imagery of the Stoics, in which philosophy is treated as a polis with its own institutions and protections. Brad Inwood argues that the Stoics took logic seriously because it governed assent, which in turn governed right action. Julia Annas notes that the image of walls and cities is traditional, and that its attribution to Zeno personally is not secure. The English is a paraphrase of a doxographic image, and it should not be quoted as a verified saying without checking the sources.