Heisenberg’s Uncertainty Principle was formulated in 1927 – but scientific thinking has not stood still since then. Heisenberg stated that it is impossible to simultaneously accurately fix (or measure) the position and momentum of a sub-atomic particle. This means that it is impossible to simultaneously fix (measure) or define time and energy. In the vacuum state, conventional logic dictates that there should be no sub-atomic particles existing in this quantum state (i.e. exactly zero energy at all times). On occasion, enough energy seems to be present to apparently ‘create’ a virtual sub-atomic particle as if ‘out of nothing’. These entities are known as ‘virtual particles’ and can theoretically possess any mass and move at any speed – even faster than light. This observation implies that virtual particles could travel backwards in time. Virtual particles exist in the interval between the measurements of real (or ‘observable’) particles, and this is why they can only be said to exist when not being observed. If they could be observed, then they would not be virtual particles. However, although some scientists think that virtual particles only exist in theory, since 1947 (Lamb and Rutherford), and in various experiments after this date, the ‘effect’ of vacuum particles upon the material universe has been observed. Furthermore, there is a theory which states that virtual particles may well be directly related to dark energy and the expansion of the universe. The point is that in an apparent vacuum that should possess ‘zero energy’ – small amounts of energy have been observed, and the presence of virtual particles is a mathematical inference from this observation. In other words, there is something there – even though it seems that there is nothing there. Virtual particles appear not to be bound by the laws of physics that govern the macro-universe, but even so, it is believed that their behaviour represents a ‘higher’ scientific understanding not yet realised by the human-mind. This is why sub-atomic particles may appear to both ‘exist’ and ‘non-exist’ at the same moment. This is not a metaphysical statement or position, but is rather a mathematical probability derived from exact calculation. This is simply a matter of observational position in relation to the sub-atomic universe. It seems as if Heisenberg is not saying that virtual particles ‘do not exist’, but rather that their existence lies in the gaps between ‘observable’ sub-atomic particle activity. This could imply that the ‘virtual’ nature of these particles actually represents a ‘gap’ in current human perception, and that when human scientific understanding advances beyond its current state, what was once thought to be ‘virtual’ particles will be understood in a new light. Of course, such a development in human faculties might well render Heisenberg’s Uncertainty Principle obsolete.