Computational irreducibility is a concept in computer science and mathematics that suggests some processes cannot be simplified or predicted without actually running the entire computation. This means that to understand the outcome of certain systems, one must simulate every step, as shortcuts or formulas won't provide the answer. This idea is often illustrated using cellular automata, where simple rules lead to complex behaviors. For example, in Stephen Wolfram's work, he showed that certain patterns evolve in ways that are unpredictable, emphasizing that some systems are inherently complex and require full computation to reveal their behavior.