McCarthy's Theorem

McCarthy's Theorem states that any function that can be computed by an algorithm (a step-by-step procedure) can also be calculated using a specific set of simple operations: copying, selecting, and looping. Essentially, it shows that these basic operations are powerful enough to perform any computable task. This theorem helps define what it means for a problem to be "computable" and underpins the theoretical foundation of modern computers, illustrating that complex functions can be broken down into and built from simple, universal methods.