How much information is required to describe the entire universe? Could such a description be contained in the memory of a computer? Might we be able to, as per William Blake, see the world in a grain of sand (or as Borges said in The Aleph), or do these words require a certain poetic license to be true? Recent developments in theoretical physics provide answers to some of these questions: the answers might be important milestones in the quest for a definitive theory of reality. The study of black holes has led to the deduction of the absolute limits, the outer edges, of the information that may be contained in an area of space or in quantities of material or energy. These absolutes, and inferences based on them, suggest that our universe could in truth be “written” on a two-dimensional plane: the universe we perceive in three dimensions could, that is, be a hologram. Our ordinary, three-dimensional perception of the world would, in that case, be nothing but a deep illusion. Perhaps a grain of sand cannot encompass the world, but a flat screen might.
JACOB D. BEKENSTEIN