Hume divides the science of moral philosophy into two distinct categories: moral philosophy that considers a person primarily as “born for action” (3), and moral philosophy that considers a person as “a reasonable being” more characterized by understanding and knowledge (5). Those who take the first position prioritize virtue and happiness and are often approved of by the common person. The second group, however, is “unintelligible to common readers” (4); they focus on what is abstract or difficult to understand.

Generally speaking, those “born for action” will have widespread approval, while the “reasonable beings” will never achieve the same fame. Others will believe they “contribute nothing” to society. Humans enjoy what Hume calls a “mixed life” of activity and rational thought, yet abstract philosophy is privileged over the simple: It is precise and exact. This kind of precision and accuracy, says Hume, is advantageous in every walk of life and every field of knowledge, especially in philosophy since it takes it much closer to perfection.

The common person finds obscurity and abstractness difficult and painful, and thus shuns them. To truly liberate learning, one must “enquire seriously into the nature of human understanding” and reflect on how human beings operate intellectually (8).