We live in a universe infinitely more complex than that which is evoked by the word reality. Only the desire for pragmatic knowledge allows us to believe that things are simply that which they are: the bearers of material qualities by which we distinguish or manipulate them. We give them names, which designate their genre, and make use of them according to our fancy. They are tools or means which refer us to other things to which they have a relation. When knowledge is elevated to a science, in doing away with appearances we discover their structure, and new types of relations, expressed in the language of figures and numbers, beyond which there is only the possibility of other structures and other numbers. The object is explained either by the finiteness of human needs or by the network of scientific relations. It is what it is, nothing more.