In the dynamics of mankind one can trace out a path of contemplation about the "world," leading from early speculations to today's natural sciences. The endeavour to understand how nature works has led to the construction, still in progress, of an abstract building of great com plexity. To the uninitiated it may look more like a scurrilous sculpture resting on many legs, among them such peculiar ones as probability, relativity, quantum mechanics .... At times problems with the stabil ity of the building or sculpture arise: known facts that won't fit and can no longer be ignored start to...