Note D — Chapter I · THE PROBLEM OF ANIMAL CONSCIOUSNESS AND "CLEVER HANS"

Ideas are copies of former sensations, feelings and other psychic experiences and retain also the accidental signs which belonged to those earlier experiences. They are images in the concrete, such as the memory of a certain horse in a certain definite situation ... say a well fed, long-tailed one standing at a manger. A concept, on the other hand, is a mental construct which has its rise in ideas, or memory-images, in that their essential characteristics are abstracted. For this reason the concept has not a definite image-content. (Thus the thought of "horse" in general, is a concept. Not so the thought of a certain individual horse,——that is an idea, with a definite image-content.)