The Principles of Psychology

The’ thing’ which we perceive always resembles, as we have seen, the object of some absent object of sensation, usually another optical figure which in our mind has come to be the standard of reality; and it is this incessant reduction of our optical objects to more ‘real’ forms which has led some authors into the mistake of thinking that the sensation which first apprehend them are originally and natively of any form at all. 24 Of accidental and occasional illusions of sight amusing examples might be given. Two will suffice. One is a reminiscence of my own. I was lying in my berth steamer listening to the sailors holystone the deck outside; when, on turning my eyes to the window, I perceived perfect distinctness that the chief- engineer of the vessel had entered my state-room, and was standing looking through the window at the men at work upon the guards.