There is a certain critical black mass of condensed human thoughts that, if reached, results in an intellectual entanglement possessing psychogravitational properties: capturing all nearby thoughts and transforming them to reinforce the averaged opinions of the mass, all while allowing each respective thinker to maintain the illusion of his or her cognitive independence.
The entanglement manifests in the world as smog, and is best observed over big cities.
It cannot be moved, affected or destroyed, save by the psychogravitation of an even greater neighbouring entanglement, into which the lesser entanglement shall eventually be subsumed.
There are those who believe that human history is merely the interplay of these entanglements, and that progress itself may be defined as the gradual decrease in the total number of entanglements in existence.
It has been observationally verified that the total number of entanglements is decreasing at an accelerating rate.
The hypothesized end state of the theory of black mass entanglements, and therefore the end of human history (and perhaps time), is what philozoophers refer to as inert uniformity; or, more colloquially, The Gates of Hell.
For further reading, see:
Błłu, Escherery. Particles of Thought
Błłu, Escherery. New Particles of Thought
Ovzvynskii, B-Boris. “In the beginning was the Word, and the Word was weightless: A Prehistory of Psychogravitation.” In The Handbook of Phrontisterical Heresies
van Dyke, Kaye Phillipa. “Black Mass: The Which Over Wichita”, Journal of Cognitive Physics 94, no. 2: 131