Dear students and guests, I am honoured by being invited to this wellknown and worldwide estimated University of Cairo in order to participate to this conference with the subject “Theory and Practice" and, furthermore, to present a paper to this conference. For about two months ago, I wasinvited to come to this conference by professor Hoda El-Khouly, who two years ago was elected to membership of the Institut International de Philosophie de Paris;so since that time we are collegues. Of course, I am interested in this subject “Theory and Practice" since my early youth, i.e.: since Gertrud Leuze, my former teacher in Latin, in early summer of 1955 gave me books which contained translations of Plátọn's dialogues. But lateron the academic career lead me to fields of research somehow far away from this subject. Therefore I now am not familiar with the results in this field established by other philosophers during the past decades; and therfore it probably may happen that everything of which I am presenting here was developed by otherones already earlier and perhaps in every relevant detail. The only thing which I am sure is that I will be able to defend all the statements which I will present during the next half an hour.