The Cathedral · laboratories
Experiments you run on yourself
Each laboratory lets you watch one of the principles operate, usually on you. Nothing you do here is sent or stored; results vanish when you close the page.
Upward constraint · Emergence
The Keyhole
Chapters 3 and 7Move along the electromagnetic spectrum, from gamma rays to long radio waves. Watch for the moment your eyes can see anything at all.
Downward causation · Upward constraint
The Cascade Engine
Chapters 2, 5, 6, 8, 13, 14, 18 and 24Choose a condition of life. Watch where it starts and how it travels through the other kingdoms. The same architecture carries the wholesome and the corrosive, and every step shows how far the evidence reaches.
Always freeDownward causation
The Door That Swings Both Ways
Chapter 12Breathing runs without you most of the time. You can also take it over. Follow the circle for one minute at about five and a half breaths a minute: in as it grows, out as it shrinks. Stop if you feel light-headed.
Emergence
The Late Narrator
Chapters 19 and 21Two short experiments, interleaved. They take about two minutes. You will be told exactly what happened at the end.
Being built
These laboratories open in a later phase, each after its own conditions are met.
Upward constraint
The Two Hundred Ways
Chapter 20A field guide to the shortcuts your mind takes, sorted by where they come from. Each has a one-minute test you can run on yourself.
Downward causation
The Transmission
Chapters 5, 11 and 18Move along three generations, beginning in the Dutch Hunger Winter of 1944 to 1945. See what reached one generation's molecules, and where the evidence for inheritance stops.
Emergence
The Moral Animal
Chapter 22Give a quick verdict on a dilemma, then write your reasons. See which came first.
Emergence
The Mirror of Machines
Chapter 23Ask the question engine the same question in two framings and compare the answers.