| Title / Condition | Highlights | Price |
|---|---|---|
| On the fourfold root of the principle of sufficient reason (The Open Court library of philosophy) Schopenhauer, Arthur / Used - Hardcover | Dust Jacket | $330.69 |
| On the Fourfold Root of the Principle of Sufficient Reason Schopenhauer, Arthur / Used - Hardcover | 1st Edition | $150.00 |
| Our Knowledge of the external World: As a Field for Scientific Method in Philosophy Russell, Bertrand / Used - Hardcover | 1st Edition Dust Jacket | $100.00 |
| Our knowledge of the external world as a field for scientific method in philosophy, Russell, Bertrand / Used - Hardcover | Ex-library | $85.67 |