Our lives are constantly influenced by great thinkers of our past. Modern marvels such as the light bulb, televisions, airplanes, and the internet, are all inventions that one could argue have been in the making for the last few millennia. Hellenistic philosophers such as Plato, Socrates, Galen, Ptolemy, Archimedes, and Aristotle, have all helped pave the way for those great scientists of the modern era. One of the oldest studies by the classical natural philosophers' was optics, or the study of light and vision. The word "optics" is derived from the Greek word for eye, "ops". We know that the ancient Greeks were studying optics over two thousand years ago, and that they spent a good deal of effort in trying to understand this faculty. The natural philosophers of this era found a great interest in optics due to the fields inherent properties. Light, as viewed by the ancient Greeks could not be touched in a material sense, but its' heat could be felt, and its' beam could be seen on the wall or the ground. Light could be reflected or rebounded off of smooth, reflective, mirrored surfaces; the Greeks called this "catoptrics". These great philosophers also noticed that light would "bend" when it passes through transparent or translucent mediums, such as water; this light refraction was referred to as "dioptrics". There is evidence that philosophers in ancient Greece were so advanced that by 400 B.C.E., those dedicated to the study of optics, or "opticians", had organized and developed a mathematical theory of how the eye perceives entities. It is believed that sometime between 287 - 212 B.C.E., Archimedes developed a somewhat advanced theory of reflection, and had began the investigation of refraction. However, what we do know is from the few known texts from classical times that give us an idea as to how much people knew in ancient times about optics. Euclid's "Optics", which is lesser known than his "Elements", describes the field of optics as they knew it in Alexandria during the late fourth and early third centuries B.C.E. Euclid is believed to have advanced a mathematical perspective based on the "straight-line propagation of light" also known as "rectilinear propagation". Another text is Hero of Alexandria's "Catoptrics" which was mostly devoted to the arrangement of reflective surfaces for particular visual effects. Lastly, one of the more pertinent classical texts on the subject is Ptolemy's "Optics" which was written in the second century A.D. From these texts, in which there are no remaining original copies, we gain an idea of how much was known during this era, and how it progressed during this time. Although these texts did exhibit some differences in the small technical attributes, they all were based on the relatively same principal; sight will not occur without a "physical mediation between the eye and visible objects." The link between the eye and the visible object, however, was the unknown that has been deba...
