The explainability surface

The explainability surface represents the limit, in conceptual space, of that which can be explained.

It is broadly related to the the limits of what is visible in the universe, combining the past, present and future (our "light-cone"). But it is more restrictive and more conceptual, because all that can be observed cannot be explained, and all that can be explained cannot be observed.

• https://en.wikipedia.org/wiki/Light_cone
• https://physics.stackexchange.com/questions/25460/can-we-see-all-of-the-observable-universe
• https://www.quora.com/Why-does-the-observable-universe-have-this-shape-of-two-cones-when-its-actually-the-same-everywhere