The constant flux and caprice of mental events do not admit of the establishment of stable experimental conditions.
Hermann EbbinghausOn the basis of the familiar experience that that which is learned with difficulty is better retained, it would have been safe to prophesy such an effect from the greater number of repetitions.
Hermann EbbinghausA poem is learned by heart and then not again repeated. We will suppose that after a half year it has been forgotten: no effort of recollection is able to call it back again into consciousness.
Hermann EbbinghausThe musician writes for the orchestra what his inner voice sings to him; the painter rarely relies without disadvantage solely upon the images which his inner eye presents to him; nature gives him his forms, study governs his combinations of them.
Hermann Ebbinghaus