It might seem that there are two separate questions about universals, the question of what they are and the question why we should believe that there are such things, and that the former question should be taken first; it might seem that until you know what they are it cannot be sensible to ask whether one should believe in them. How, for example, could one know whether it was sensible or even possible to believe in Father Christmas until one knew who or what he was supposed to be? But appearances could be deceptive. In the case of universals the position is different. What happened was that philosophers found themselves faced with certain problems of which they were inclined to say: this problem is insoluble unless there are some entities which have certain characteristics, the characteristics which would enable the problem to be solved. The things which, if they existed, would solve their problems they called forms or universals. So universals are things which have whatever properties they need to have to solve certain problems. This being so, it is clearly sensible to approach the theory of universals from the problems which led to philosophers postulating their existence.