Science is a differential equation. Religion is a Boundary Condition.1
— Alan Turing
When Turing wrote "Science is a differential equation. Religion is a Boundary Condition", I think he meant that science and mathematics are abstractions we've invented, and improved upon over millennia, to help us to objectively explain things using logic & reason as we humbly strive for intellectual honesty — not unlike how differential equations objectively model the dynamics of phenomena in space and time.
Turing's metaphor that religion is a boundary condition refers to an observable human foible that whenever we bump up against the limits of comprehension, we make shit up.
- Epigram to Robin Gandy (1954); reprinted in Andrew Hodges, Alan Turing: the Enigma (Vintage edition 1992), p. 513.