Reality+: Virtual Worlds and the Problems of Philosophy

by David J. Chalmers

Babylonian text, the Enuma Elis, dating from sometime before 1000 BCE, recounts a cosmic history in which the world is formed by gods representing earth, wind, sky, and sea. The Indian Vedas, around 1500–500 BCE, make frequent reference to five basic elements: often earth, air, fire, water, and space (or aether or void). The ancient Chinese Wu Xing system, dating from around 200 BCE, suggested five elements in an eternal cycle: Wood feeds fire, which creates earth, which bears metal, which collects water, which nourishes wood. In modern times, earth, air, fire, and water have been decomposed into more basic components, all the way down to quarks and electrons. Two other ancient Greek ideas have worn much better. Pythagoras, who lived around 550 BCE, suggested that everything is made of numbers. The number 1 represents the origin of all things, 2 represents matter, 3 represents beginning/middle/end, 4 represents the four seasons, and so on. While the specifics of the Pythagorean system may not have lived on, the idea that reality is fundamentally mathematical is still taken seriously today—as in the it-from-bit hypothesis, which might be understood as saying that the world is made up of the numbers 0 and 1 in patterns.