The Triune Stack

To understand the conflicts in your mind—why you want to diet but eat the cake, why you want to be calm but scream—you must understand that your brain is not a unified design. It is an archaeological site.

Paul MacLean introduced the concept of the Triune Brain. While modern neuroscience has added nuance to this model, it remains the most powerful heuristic for understanding your internal civil war.

Layer 1: The Reptile (Basal Ganglia)

At the base of your skull sits a lizard. This is the Brainstem and Basal Ganglia. It is 500 million years old. It cares only about survival: feeding, fighting, fleeing, and reproduction. It is cold, rigid, and fast.

Layer 2: The Mammal (Limbic System)

Wrapped around the reptile is the Limbic System. This is the seat of emotion, memory, and social hierarchy. It allows you to bond, to feel rage, and to remember pain. It is warm, messy, and reactive.

Layer 3: The Human (Neocortex)

On top lies the Neocortex. It is the CEO. It plans, calculates, and imagines the future. It allows you to write poetry and build starships.

The Inheritance of Perspective

Your suffering often comes because these layers disagree. The Lizard wants safety; the Human wants meaning. The Mammal wants love; the Human wants logic.

Do not hate your "lower" nature. You cannot kill the Lizard without killing the body. You must learn to parent it. The goal of this Codex is to put the Human back in charge, while honoring the beast that keeps you alive.