The roots of optics
The roots of optics, the oldest discipline in physics, can be traced back to the ancient world, where philosophers such as Pythagoras, Ptolemy and Plato advocated the theory of ›rays of vision‹, whereby light was thought to originate in the eye itself and—similar to a lighthouse beam—scan the outside world. The mathematician Euclid (3rd c. BC) described these ›rays of vision‹ as emanating linearly from the eye and being reflected by the outside world.