To the gross senses the chair seems solid and substantial. But the gross senses and be refined by means of instruments. Closer observations are made, as the result of which we are forced to conclude that the chair is “really” a swarm of electric charges whizzing about in empty space. ... While the substantial chair is an abstraction easily made from the from the memories of innumerable sensations of sight and touch, the electric charge chair is a difficult and far-fetched abstraction from certain visual sensations so excessively rare (they can only come to us in the course of elaborate experiments) that not one man in a million has ever been in the position to make it for himself. The overwhelming majority of us accept the electric-charge chair on authority, as good Catholics accept transubstantiation.

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