Preface to the Abhandlungen zur Philosophie der Mathematik (1974)

The Wissenschaftliche Buchgesellschaft has kindly offered to publish a collection of my essays on the philosophy of mathematics, which have appeared in various journals. I accept this offer gladly, in particular since several of these essays are not easily accessible. The present volume can also serve as a temporary substitute for a comprehensive treatment of the philosophy of mathematics. This is possible because, during the period in which these articles were published, my views on the relevant questions have changed almost exclusively in response to new insights gained from research in the foundations of mathematics. A monograph on this topic, to be published by Duncker & Humblot, has long been planned (but is still not done).