dissertation submitted to the Faculty of the Division of the Humanities
in Candidacy for the Degree of Doctor of Philosophy, Department of Philosophy,
The University of Chicago, 1966.
version for Internet has been revised minimally by the author in 1998,
mainly for style.
study was thought out and written in a period of two years during which
I was able to dedicate myself completely to academic research and philosophical
reflection. This singular opportunity was made possible by two generous
grants of the Ford Foundation and the John Simon Guggenheim Memorial Foundation.
To both institutions I want to express my deepest