Why can't programs be proven?

Question

Why can\'t a computer program be proven just as a mathematical statement can? A mathematical proof is built up on other proofs, which are built up from yet more proofs and

Answer 1

The halting problem only shows that there are programs that cannot be verified. A much more interesting and more practical question is what class of programs can be formally verified. Maybe every program anyone cares about could (in theory) be verified. In practice, so far, only very small programs have been proven correct.