In the following paragraph he writes "The individual life of the human spirit contains incongruent elements, such as tenets of faith and superstition which, stemming from various individual complexes, muddy the purity of any theory or system. Both Kepler and Newton, who contributed so much to the modern concept of nature, were ritualistic and religious in thei basic attitudes. Rousseau's idea of education had much greater relevance to the thought collective than to his own individual life." (57.9-58.1)
The point would seem to be that a person can switch, as it were, between various "thinking orbits" but when ideas are put into circulation they lose nuance and gain solidity as they are repeated back and forth among people. They might fade in importance for their originator even as they become established in the group.