The modern scientific age began when Nicholas Copernicus proposed that the earth revolves around the sun. His ideas were later improvised by scientists like Kepler, Galileo, and notably by Isaac Newton, who discovered laws that governed the motion of the physical bodies and the law of gravitation. Further, James Clerk Maxwell showed that magnetism and electricity too could be deduced by a set of equations. The philosophical implication of these scientific developments is that the whole universe is determined by physical laws. This is called the principle of determinism. This law was prevalent in scientific circles up to the end of the 19th Century.