Based on the question you asked I think he meant that one race cannot stand on its own it needs another race to come together to build a better nation. If the blacks are slaves and the whites are free then the nation will tear apart because you need both people of the nation to come together to make the nation better and the people better.
As a list of all of the examples of the concept that the individual has encountered.
Explanation:
<u>Exemplar theory:</u> There are certain concepts and analyses of the different objects which brings about the conclusion of which the professional requires and then they get the idea about the different properties and orientation of the object that are under consideration.