About The App Code

The App Code is an independent encyclopedia of the ideas that make reasoning better — mental models, cognitive biases, and how-to-think explainers. Every page answers two questions plainly: “What is this?” and “How do I actually use it?”

Entries follow one rigorous template: a one-line definition, a plain-language explainer, a worked example, the failure mode (when the idea misleads), the related models and biases, and a short “how to apply it” takeaway. Pages interlink densely, so following an idea to the ones it connects to is the whole point.

We are evidence-minded and honest: we cite origins where a model has a named source, we state each idea's limits, and we publish no fabricated studies or statistics. This is a reference for reasoning — not therapy or clinical advice. See how we write and our sources.