Einstein espoused in many of his essays the opinion that there is no logical and direct path from from the world of experience to a set of concepts to describe and understand/organize that experience. The concepts and ideas that we use to describe nature are free creations of the mind. For example, mass is not a property of objects, but a property of our description of our sense-experience of objects. This became very clear with the advent of the general theory of relativity, which described in a completely satisfactory way the same domain of experience (and more) with a different set of concepts than the one used by Newton in his system of mechanics. What is unclear to me is whether this implies that there is no uniquely natural description. For example, the primitive concepts of everyday life seem to be uniquely suited to the description of our restricted experience. These include our Euclidean geometry intuition, Galilean view of spacetime etc. Maybe if our experience was wider, evolution would have provided us with another set of concepts which are naturally suited to describe that experience. It's not hard to imagine that the wider our experience, the closer our intuitive concepts and ideas will be to some natural and unique set of concepts. Any thoughts?