[209] LECTURE XVIII, Dec. 6, 1955 The discussion last time tried to show that there is no philosopher without an existential foundation, without an ultimate concern. On the other hand, l said that in the arena of philosophical discussion this ultimate concern is not supposed to enter, but that this discussion has to go its own way in terms of philosophical arguments. I tried to show this in connection with different philosophical groups, especially the difference of naturalism^a and idealism^b, and nominalism^c and realism^d. In both cases it was obvious that there is an element of ultimate concern IN WHAT PEOPLE SEE, in what they ASK, in the whole existential situation out of which their philosophical problems are born. Now I don't want to continue this now. Of course it could be shown in almost every individual philosopher. I only need to refer to people like Plotinus,^e in whom the Egyptian mystery religions determine the questions and partly answers, although he is on the other hand one of the most rational and logically-minded of the Greek philosophers. I could refer to a man like Spinoza^f in whom the fundamental Jewish monotheism is united with a concept of nature as it has developed since the Renaissance. I could even refer to a man like David Hume,^g in whom the nominalistic (or, better, Calvinistic) attitude towards reality---the distance-from-the-ultimate of the surface of existence in which we are moving----produces his form of positivism. That doesn’t take away in any way the weight of the positivistic argument---certainly not---but it takes away the belief that in a skeptic like Hume, or in a positivist like Hume, the ultimate concern is absent. It is in no way absent, and it shows itself