An excerpt from the book I’m currently reading, ‘Psychology’ by George A. Miller..
“You have three basins of water. In one the water is cold, in the second it is tepid, in the third hot. Put one hand into the cold water and the other into the hot. After you leave them immersed a minute or two you will discover that the difference in warmth disappears. When your two hands seem to be approximately the same neutral warmth, remove them both and plunge them into the remaining basin, the one containing the lukewarm water. Now the water here seems to have two temperatures at the same time, warm to one hand and cool to the other. But you know that the water must have a single temperature! It is not reasonable to say that the same water is both warm and cool simultaneously, even though it feels that way. Something has gone wrong with the usually reliable machinery for finding out about the world we live in.
The dilemma of the three basins was used by John Locke in 1690 as part of his argument that the apparent qualities of objects – warmth, for example – are not in the objects themselves, but in the minds of the persons who perceive the objects. The object is not warm, said Locke; it merely possesses the capacity of arousing the idea of warmth in us. If the warmth we perceive were truly in the object itself, as it appears to be, it would be impossible for us to perceive two different warmths in one object at the same time..”
...Concerned about appearance and reality, seeming and being, or just whether the water’s hot or cold? Worry no longer, modern science has come up with a solution – The Heat-Sensing Faucet Light! Glows blue when the water is cold and gradually turns red as it heats up..