Kleene recursion theorem

The Kleene recursion theorem states that in computational systems, it's possible for a program to "know" its own code. Specifically, a program can be designed to access and incorporate its own instructions or description during execution. This means it can generate or modify other programs, including itself, based on its own structure. This self-referential capability is fundamental for tasks like creating self-replicating code or tools that customize their behavior, highlighting the deep link between programs and their descriptions in the theory of computation.