Abstract

This is a presentation of Bolzano's ideas on logic, logical semantics, ontology, proof theory, the foundations of mathematics, and certain aspects of the philosophy of nature. Bolzano's world view was a universal one in the sense that philosophy, mathematics, physics, and metaphysics should build upon the same logical foundation. In the pursuit of this encyclopaedic point of view he already recognized many of the essential things to come in logic and the foundations of mathematics