Studies of animal vision suggest that different species have very different visual experiences of the world. Cats and dogs, for example, are red-green colour blind, although they see more in the periphery and at night, while snakes can 'see' infrared frequencies at night although not things that keep still. Horses, with eyes at each side of the head, see a greater panorama than humans, while insects like flies and bees have compound eyes which make up a mosaic-like image composed of many individual units. Some insects, like butterflies, see more colours than us, while others, like bees, see less but can see in the ultraviolet spectrum.
What appears to humans, with our particular perceptual apparatus, as reality will appear quite different to another species. Something that is an object to us may not be to a fly, and vice versa. This tells us that the way the world is divided up according to human perception is not the only way it can be divided up, and that in fact what constitutes reality is something of a moveable feast depending on the structure of the perceptual systems being used. Reality is subjective.
