The author believes that a "genial heat is latent in all constitutions, and is disengaged only by the friction of society" (paragraph 3) because:
a.) people's animal spirits are constrained until drawn out through interactions with society.
b.) people realize the power of memory only when members of society touch upon something from the past.
c.) people are naturally warm and caring unless they get into a disagreement with another member of society.
d.) people's ability to provide for others depends on their ability to interact with society.