or they are dispositions of physical objects to produce visual states of colour (dispositionalism). This view combines the previous two into a sort of bit of both' theory and ponders the question whether perhaps objects, though having no colour attribute, do have a mechanism which disposes the observer to attach colour to the perception of it.
Science, especially physics, holds the view that the colours we naturally consider objects to posses is as such an illusion, and that these physical objects do not possess any such an attribute whatsoever. It proposes that colour is entirely perceiver dependent, which is that the impression of colour which an object seems to posses is produced by, and in, the observer subject alone. The observer attaches colour through the process, or mediation, of perception to the object in view. Objects themselves play no part in the attributing of colour excepting the phenomena of reflection and refraction of specific electromagnetic waves whose source is independent of them. In this model, electromagnetic emissions from a source, ie the Sun, fall upon an object, ie grass, and the composition of the object's surface is so arranged chemically and elementally at a molecular level, as to reflect the emissions of certain wavelengths, e.g. in the case of grass an electromagnetic wavelength of around 500 to 550 nm. These reflected emissions pass into the eye of an observer where, through a process of photochemical and neurological events, it produces a sensation within the brain to which is attached a language predicate, e.g. in this case green or greenness. Even before modern science was able to measure and observe this type of phenomena, Galileo and Descartés questioned the view that mere appearance was all that lay behind the existence of colour. On the senses, Galileo remarks "I think that tastes, odours, colours, and so on are no more than mere names so far as the object in which we place them is concerned, and that they reside only in the consciousness.
