The classical concept of 'physical entity', be it particle, wave, field or system, has become a problematic concept since the advent of relativity th… - Diederik Aerts

In classical Newtonian physics there was a clear understanding of 'what reality is'. Indeed in this classical view, reality at a certain time is the collection of all what is actual at this time, and this is contained in 'the present'. Often it is stated that three dimensional space and one dimensional time have been substituted by four dimensional space-time in relativity theory, and as a consequence the classical concept of reality, as that what is 'present', cannot be retained. Is reality then the four dimensional manifold of relativity theory? And if so, what is then the meaning of 'change in time'?

World views, as related to the sciences, ethics, arts, politics and religions, are integral parts of all cultures. They have a strongly motivating and inspiring function. A socially shared view of the whole gives a culture a sense of direction, confidence and self-esteem. Moreover, interactions between cultures change constantly.

We are quickly approaching the end of the millennium and the 'magical' year 2000. Many futurologists in the sixties thought science and technolo­gy would offer man unprecedented possibilities for solving his problems. The fall of the Iron Curtain and the implosion of the Eastern Block also created, just a, few years ago, grand expectations. The dream did not come true, however. Rather than ending up in a technological paradise and a peace-loving world, we woke up in a torn world with virtually unsolvable environmental problems and agonising social conditions.