I have a hypothesis that the past doesn't exist until an observation in the present makes it necessary. That seems the simplest form of a universe. And nature likes simplicity, right?
The least amount of information necessary to create a perceived reality is whatever the actors in the reality experience at the moment plus an artificial history that is created on demand, as events in the present require.
My limited understanding of physics is that retrocausality is allowed. And of course our common notion of "time" is nowhere near what is actually happening in the universe. Physicists refer to space-time instead. Whatever that is.
Is there an existing philosophy or hypothesis that matches my idea that history is created on demand?
UPDATE: Reader Amit informs me that there is an existing philosophy that matches the idea of on-demand history as well as the idea that we are all computer simulations.