From the lowest animals of which we can affirm intelligence up to man this type of intellect is found.
The real difference between a man's scientific judgments about himself and the judgment of others about him is he has added sources of knowledge.
This growth in the number, speed of formation, permanence, delicacy and complexity of associations possible for an animal reaches its acme in the case of man.
The intellectual evolution of the race consists in an increase in the number, delicacy, complexity, permanence and speed of formation of such associations.
There is no reasoning, no process of inference or comparison; there is no thinking about things, no putting two and two together; there are no ideas - the animal does not think of the box or of the food or of the act he is to perform.
Human folk are as a matter of fact eager to find intelligence in animals.