Perceived colour is the result of some kind of selection of wavelengths from the incoming light, and interpretation by the eye-brain system. The colours that you saw at the top of the page were created by a rather complicated process, involving not only the five mechanisms listed earlier, but also the following - A slide film and processing A scanner which produced a stream of digital data, A program which converted the data into JPEG format, A cathode ray tube or a TFT screen which interpreted the data using three coloured phosphors. Your own vision. We find a fascinating world behind even the simplest observations. The different kinds of science, like the different kinds of art, provide entrances to ways of understanding that are outside the essential tasks of getting food and drink and shelter.
People have the ability to create abstract ways of thinking.
Even something so mundane as money, presumably created to avoid the complications of bartering, has led to the complex worlds of finance and economic theory. Some people think that science is difficult, which it is - otherwise we would all be able to do it. But it is not necessarily more abstract than many other things that people take for granted.