The word 'belief' is a difficult thing for me. I don't believe. I must have a reason for a certain hypothesis. Either I know a thing, and then I know it - I don't need to believe it.
Just as we might take Darwin as an example of the normal extraverted thinking type, the normal introverted thinking type could be represented by Kant. The one speaks with facts, the other relies on the subjective factor. Darwin ranges over the wide field of objective reality, Kant restricts himself to a critique of knowledge.
We are born at a given moment, in a given place and, like vintage years of wine, we have the qualities of the year and of the season of which we are born. Astrology does not lay claim to anything more.
We are in a far better position to observe instincts in animals or in primitives than in ourselves. This is due to the fact that we have grown accustomed to scrutinizing our own actions and to seeking rational explanations for them.