I have been reading some books (Allendoerfer, principles of math, Zakon, series of mathematical analysis, R. Courant, what is mathematics). I have learned that some of the basic fundamental, the msot bare bones of mathermatical concepts and definitions have to remain undefined. These are set, element, point, line, proposition, true, false. Other technical terms are later defined in terms of these. What do I make of this? we have an intuitive guide to all these terms and certainly treat them as we know what they are. We were discussing this with friends, and I simply stated one of courants views roughly as being the student should not be concerned with the philosophy or nature of mathematical objects, rather it is the relations and operations between them that are more important. It still blows my mind somewhat.