Simple rule of inference that states:
implies . is true, therefore must also be true
In symbolic statement:
See also
- Hilbert’s program was to formalize all of math, disproven by Gödel — Hilbert’s program aimed to reduce all of mathematics to mechanical inference rules like this one
- Gödel’s incompleteness theorems — Gödel showed that even a system grounded in rules like modus ponens cannot prove all truths about itself