This idea challenged a basic premise of slavery—a premise that Foster must have believed without reservation: that the Africans had been nothing but savages, with no humanity or human feelings, and therefore it was all right to enslave them.
This is not so terrible in itself and I must say that my parents tried to answer every one of my questions very patiently, until...I began even badgering strangers, and they generally can’t stand “children’s endless questions.”
I must admit that this can be very tiresome, but I console myself with the idea that there is a saying that “you must ask in order to know,” which couldn’t be completely true, otherwise I’d be a professor by now.
motivation deriving from ethical or moral principles
Even a very small child is a little personality and has a conscience and should be brought up by being treated in this way, so that it will feel that its own conscience is punishing it in the harshest way possible.