The ghost phenomenon is all about information.<p>When a system has a lot of complexity, it needs a lot of computational resources to be simulated accurately.<p>When suddenly this complexity is not needed anymore, because the system got "simplified" suddenly. The pockets of available computation diffuse slowly into the environment.<p>The analog for the scientific person here is like your adaptive grid in the simulation was locally in high resolution because it was needed by the physical process, and suddenly the physical process doesn't need it anymore but the simulation grid stays in high resolution.<p>When some other high complexity process comes nearby (like another rich soul), it benefits from this increased resolution which usually allows him unconsciously to run his computational wetware in higher gear, like in a form of mildly induced schizophrenia, vivid dreams, or hallucinations.<p>Brains as general information analyzing devices can perceive the shape of this echo from the past, decoding from the faint ripples the stone that impacted the water.<p>The mythology of absorbing the essence from the passed is varied across time and places, ranging from soul capturing gems, the fighting to survive against the erosion of time like in Highlander accumulating the energy of your rivals by eating their brain.<p>Looking at it only as a physical process ("real") will make you miss it. It has to be seen through the lens of the ethereal plane. Information is conserved, but details can be compressed more or less. Degrees of freedom accumulated or used are different things.