The musician writes for the orchestra what his inner voice sings to him; the painter rarely relies without disadvantage solely upon the images which … - Hermann Ebbinghaus

Mental events, it is said, are not passive happenings but the acts of a subject.

No matter how thoroughly a person may have learned the Greek alphabet, he will never be in a condition to repeat it backwards without further training. But if he chances to set out purposely to learn it backwards, he will probably accomplish this in noticeably shorter time than was the case in the previous learning in the customary order.

Natural science served as - if we overlook the hasty identification of mind and matter which had its origin in natural science - as a shining and fruitful example to psychology.