Education: Being and Time

"He who does not know what homesickness is," he declared, "cannot philosophize." For Martin Heidegger, who died last week at 86, the sickness was that of the soul and the home was nothing less than existence itself.

Heidegger's own existence was an embodiment of modern philosophy. The son of a Roman Catholic sexton in southern Germany, Martin was first attracted to the priesthood. At Freiburg University, his theological interests were deflected to mathematics and science and finally to philosophy, which for him was a matter of life and death.

Radical Renewal. From its beginning, Heidegger's career was marked for controversy. His professors at...