perennial problems through the centuries and are still discussed today. The answer is given in the light of our knowledge today and with the help of modem logic. But the book explicitly aims at connecting recent problems with re­ lated ones in the whole history of philosophy. The method to incorporate important philosophers of the tradition into the analysis is that of disputation, i. e. of putting some of their main thesis into objections or counterobjections pro or contra a posi­ tive answer to the respective question. After the pros and cons are given a detailed answer to the question is proposed and finally commentaries and corrections are given to the objections and counterobjections in the light of the proposed answer.