The theory of direct perception and the concept of affordances in specifying decision support systems
Any appearances whatever present themselves, not only when its object stimulates a sense, but also when the sense by itself alone is stimulated in the same manner as it is by the object.
Aristotle 330 BC
Upon every great agitation or concussion o f the brain whereby the optic nerve suffereth any great violence, there appeareth before the eye a certain light, which light is nothing without, but an apparition only, all that is real being the concussion,
Thomas Hobbes 1651
That which through the medium o f our senses is actually perceived by the sensorium is indeed merely a property or change o f condition o f our nerves; but the imagination and reason are ready to interpret the modification in the state o f the nerves as properties o f the external bodies themselves.