CLOSED MIND

The Greek philosopher Aristotle (384–322 BC) wrote that the perfect circle is the ideal form in geometry. On this basis, he argued that since nature always works in a perfect way, the paths along which it moves the heavenly bodies must also be perfect circles. This idea of Aristotle dominated people’s minds in ancient times. The astronomical systems developed in those days—for example, those of Ptolemy, Copernicus, and Tycho Brahe—all assumed that the planets of the solar system revolve in perfect circles in space.

Johannes Kepler (1571–1630) was probably the first person to challenge this. In 1609, through calculation, he showed that Mars does not move around the sun in a perfect circle but in an elliptical orbit. He predicted that the orbits of all the other planets around the sun must also be elliptical. Today, Kepler’s view is a well-established fact.

For two thousand years, ancient astronomers remained absorbed in the idea of the perfect circle. They could not think differently about the motion of the planets. The reason was the authority of Aristotle’s idea. They accepted it without debate as an unquestionable truth, and because of that, their minds could not move in any other direction.

This is not just a matter of ancient times—it is true in every age. In all eras, certain ideas dominate people’s minds so completely that they find it impossible to think independently outside of them. This happens in both religious and non-religious fields. Such a closed mind is the biggest obstacle to progress of any kind.