For a system of logic to be able to express Gödel numbers, it must be able to assign unique numerical values to each symbol, formula, and proof within the system. This requires a well-defined and consistent method for encoding the symbols and formulas of the system as numerical values.

In order to construct a Gödel numbering, each symbol of the system must be assigned a unique prime number, and each formula must be assigned a unique composite number that is the product of the prime numbers corresponding to its constituent symbols. Proofs can then be assigned Gödel numbers by encoding them as sequences of formula numbers, and using a well-defined encoding method to convert those sequences into a single numerical value.

The ability to assign unique Gödel numbers to each symbol, formula, and proof within a system is a necessary condition for the system to be able to perform Gödel's incompleteness theorem, which demonstrates the inherent limitations of any formal axiomatic system. This theorem shows that any formal system that is powerful enough to express basic arithmetic must either be incomplete (i.e., some true statements cannot be proven within the system) or inconsistent (i.e., both a statement and its negation can be proven within the system).