Galileo claimed that “mathematics is the language in which the book of nature is written” and no more is this apparent than in our most successful theory of nature, quantum field theory. As the mathematical backbone for The Standard Model, quantum field theory’s numerical predictions have been experimentally verified to the highest precision, however, as Timothy Nguyen argues, predictive success alone is not enough for a fundamental theory of reality and only with the safeguard of rigour can science separate truth from fantasy.