1. Descartes' Meditations as the prototype of philosophical reflection. I have partieular reason for being glad that I may talk about transeendental phenomenology in this, the most venerable abode of Freneh seienee.l Franee's greatest thinker, Rene Deseartes, gave transeendental phenomenology new impulses through his Meditations; their study aeted quite direetly on the transfor- mation of an already developing phenomenology into a new kind of transeendental philosophy. Aeeordingly one might almost eall transeendental phenomenology a neo-Cartesianism, even though it is obliged-and preeisely by its radieal development of Cartesian motifs - to rejeet nearly all the well-known doe- trinal eontent of the Cartesian philosophy. That being the situation, I ean already be assured of your interest if I start with those motifs in the M editationes de prima philosophia that have, so I believe, an eternal signifieanee and go on to eharaeterize the transformations, and the novel for- mations, in whieh the method and problems of transeendental phenomenology originate. Every beginner in philosophy knows the remarkable train of thoughts eontained in the Meditations. Let us reeall its guiding idea. The aim of the Meditations is a eomplete reforming of philosophy into a scienee grounded on an absolute foundation.