Evolution of our Knowledge

To improve their conditions of life, human beings used their growing knowledge about the reality from the very beginning. Unexplainable changes of states they attributed at first to the different gods of nature. The more they understood the laws of nature the more rational explanations they found.

Human knowledge about the reality started with the experience obtained directly by activities in that reality. Later experiments and observations on Earth and in the cosmic space provided more information. The assessment of the received data required, however, subjective a priori assumptions about the reality.

The ancient Greek philosophers formulated about 2500 years ago a first rational world picture. Thales and Anaximander supposed for the cosmos primordial matter. For Thales it was the water, for Anaximander the boundless “Apeiron”. Other ancient philosophers formulated other ideas. The resulting world picture supported not only the improvement of the conditions of life under the given natural conditions, but also the improvement of human living in societies. Ancient Greek became the cradle of democracy.

The neediness of an ordered life in societies contributed also to the transition from the polytheistic religions of nature to the monotheistic religions with strong commandments for the behavior of the individuals in societies, formulated, for instance, as the 10 commandments of the Bible.

The Bible implied the ancient geocentric world picture, in which the celestial objects rotate around the Earth. This picture became a dogma of  Christian church. In the 17th century, the founders of modern physics replaced it by the heliocentric picture, in which the Earth rotates together with the other planets around the Sun. The stars became fixed stars.

The heliocentric world picture opened the way to physics as a modern science of nature. Giordano Bruno (1548 – 1600) replaced the infinity of god by the infinity of space. He was burned at the stake in Rome. Later René Descartes (1596 – 1650) and Blaise Pascal (1623 – 1662) denied the existence of a space in the reality.

For the basic questions of the rational interpretation of the reality, philosophy introduced the term “metaphysics”. The Greek prefix “meta” means “behind” physics. The term denoted initially the 14 papers of the ancient Greek philosopher Aristotle (384 – 322 BC). Later it denoted all rational a priori assumptions physics needed to describe reality. Kant (1724 – 1804) spoke of the „metaphysics of nature“.

An important issue of metaphysics is the interpretation of space and time. With the development of modern physics, space and time became constituents of the reality. By his law of a falling body, Galileo Galilei (1564 – 1642) defined space and time as physical quantities. Newton (1643 – 1726) assumed an absolute immovable space, in which the bodies as the observable discrete objects of matter move. The time he considered as absolute and uniformly. He succeeded thus determining the positions and motions of the bodies according to the observations.

Classical optics assumed the massless ether in space as transmitter of the light waves. With the discovery of the electromagnetic fields in the 19th century, the space became physical properties. Even more. As by an experiment the velocity of the Earth through the cosmic space did not add with the speed of light, the contraction of space was assumed. Einstein (1879 – 1955) explained it by his theory of special relativity of 1905. The a priori principles, applied in the theory, determined with the space contraction mathematically the time dilation.

With the theory of general relativity of 1915, Einstein explained gravitation by the curved space. Later cosmology added the expansion of the cosmic space to save the speed of light as the limiting velocity for all relative motions of the matter components.

The particle physics of the 20th century contributed its own a priori assumptions to the physical world picture, concluded either from experiments, either from the theories themselves. Examples are the “wave-particle duality” and the “nonlocality” of changes of states. By the wave-particle duality, the observer should decide whether the particles are lokalized discrete objects of matter or spatially extended waves. Nonlocality means interactions without the exchange of impulses. An interpretation that Einstein opposed vehemently.

With their current theories and models, particle physics and cosmology describe more or less virtual realities. They succeeded thus explaining experiments and observations in a rational way, however, sometimes in conflict with other experiments and observations, sometimes in conflict with direct human experience.

The meanwhile available technics and technologies require for human activities in the natural environment and in  human society an interpretation of the reality that is concistent with human knowledge today. Only this would allow avoiding dangerous developments for future human civilization. Physics should contribute to such interpretation.

It needs a priori assumptions about the reality formulated in full consistency with all experimental and observational data available today. Another criterion should be the full consistency of the theories and models with human direct experience. Finally, the mathematics applied should describe reality without virtual features. It should obey the laws of nature strictly, based on the correct interpretation of space and time. Mathematics itself is not a proof of the correctness of theories and models.

The following contributions were formulated considering these aspects.