Werner Heisenberg (1901-1976) gave his famous Uncertainty Principle based on this overlapping concept of wave-particle duality. He showed that all matter behaves sometimes as a wave and at other times as a particle. It is the very process of observation which determines which aspect of matter is revealed to us the Observer. As long as the entity is not disturbed it behaves like a wave. The moment we try and pin-point it the particle nature pops up. This switching of nature is significant at the atomic level and lends itself to an Uncertainty in measurement during experiments. It limits our capability of knowing exactly either the position or speed of the particle. The precision in trying to locate the spot at which the atomic entity is results in indeterminacy in knowing how fast it is moving – we cannot measure both aspects with infinite precision. The everyday billiard-ball concept of the particle literally goes out of the window. It has to be replaced by a fuzzy cloud of mathematical probability.