Date: 1902

"If it were otherwise, no one could even set down on paper a closely reasoned argument, for the attention would be skipping like a stone hurrying down a sharp incline, or it would be moving hither and thither like a helpless shuttlecock at the mercy of eager players."

— Spiller, Gustav (1864-1940)

Date: 1911

"I shall here have to change my metaphor a little to get the process in his mind. Suppose that instead of your curved pieces of wood you have a springy piece of steel of the same types of curvature as the wood. Now the state of tension or concentration of mind, if he is doing anything really good...

— Hulme, T. E. (1883-1917)

Date: 1999

"On its own this trigger, as we can see from the earlier definition, is not going to generate consciousness. Imagine a candyfloss machine with a stick in the centre that then gathers more and more candyfloss as time goes on. Think of the epicentre as the stick in the centre, the burgeoning candy...

— Greenfield, Susan (b. 1950)