Through the man with the club, Buck is introduced to "the reign of primitive law" (Chapter 1). This law says that "those with the greatest physical strength are the rulers" (enotes link referenced below). After being brutally beaten down time and again, Buck understands that he stands no chance against a man with a club. Such a man is "a law-giver, a master to be obeyed". A hierarchy is established, and although Buck's spirit remains unbowed, he knows he must submit if he is to survive (Chapter 1).