Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

The Joke

A man enthusiastically tells his companion that he loves exploring his own mind through introspection: the more he digs, the more interesting things he discovers about himself, and most people do not realize how much is down there. His companion responds with a skeptical "hm." The man insists they try it too. In the next panel, a group of miners with headlamps appears underground, and one announces, "Notify the foreman! We've found a rich new vein of denial!"

The comic uses the metaphor of mining to literalize the concept of introspection. The man believes he is bravely exploring the depths of his psyche and finding treasures, but when someone actually "mines" his mind, what they discover is not profound self-knowledge but rather a massive deposit of denial. His very enthusiasm about his own self-awareness is itself evidence of how little self-awareness he actually has.

The Humor

The punchline works through a double irony. First, the man's confident claim that introspection reveals wonderful things is undercut by the miners' discovery that his mind is primarily composed of denial -- the one psychological defense mechanism that, by definition, prevents you from knowing it is there. Second, the mining metaphor is played completely straight, with hardhats and a foreman, which makes the abstract psychological concept tangible and funny. The phrase "a rich new vein of denial" treats self-deception as a natural resource, abundant and valuable in its own way. The comic suggests that the people most convinced of their own self-knowledge are often the least self-aware.