The comparison between acquired and innate capacities of animals shows a similarity between kinaesthetical and instinctive actions.
Both kinaesthetical and instinctive action can be performed independent of their aim.
Observation and instinct act in both cases in principally the same way as an inducement to action.
These considerations lead to the hypothesis that instincts are kinaesthetical habits which have become hereditary. It is possible to solve this problem experimentally.