The tone of Donna Tartt's The Secret History is contemplative and dry. As the first-person narrator, Richard is somewhat flat and unemotional, even when he discusses things as sensitive as his family life in California or his romantic relationship with Sophie Dearbold. In fact, Richard is so unaffected, particularly following Bunny's murder and Henry's suicide, that Sophie ends their relationship.
However, Richard's emotional indifference actually makes him the perfect person to get away with murder unscathed. His ability to keep his emotions bottled up inside him allows him to escape the federal investigation without "a blink of suspicion."
Richard's dry personality and overall apathy, though, does not preclude him from being a highly philosophical and introspective character. The reader can see in Richard's actions that he does care deeply about certain people and ideas, even if the thought process is not apparent. He cares enough for Camilla to propose to her in the epilogue, and he cares enough about first impressions to falsely romanticize his life in California.
Even though Richard did not grow up in an intellectual and upper-class household like the other Greek students, he similarly incorporates academic allusions into his thoughts. Doing so allows him to blend in with his peers and makes him feel like he truly belongs in Julian's classes at Hampden College.