One of the more difficult things to do in fantasy is to create a system of magic that works in a consistent and believable way. Pratchett embeds real-world rationale into The Color of Magic by showing his characters employing the scientific method to study their magical world. The scientific method is the process of observation and experimentation used to gather data and develop theories about the world. On the Disc, this means that cosmochelonians debate the Steady Gait theory versus the Big Bang: “the theory that A’Tuin had come from nowhere and would continue at a uniform crawl, or steady gait, into nowhere, for all time” versus the idea that “A’Tuin was crawling from the Birthplace to the Time of Mating” along with other giant space turtles, who would mate and create new turtles carrying new worlds (4). These theories, of course, are parodies of creation myths and scientific hypotheses of our actual universe.

Pratchett’s science of magic parallels the science of Roundworld (our earth). Magical fields replace gravity and influence the speed of light. They also act like radiation, causing mutations and strange effects on their surroundings. Instead of the law of conservation of mass, the Discworld has the “Law of Conservation of Reality; this [demands] that the effort needed to achieve a goal should be the same regardless of the means used” (82).