Do theorems need to be proved? - Answers

By definition, a theorem is a proven statement- until a proof is made for a statement, it is not a theorem but rather a conjecture. Whether you need to be able to reproduce the proof of a known theorem is another matter. If you trust the prover, I think you can make use of a theorem without knowing the proof. However, studying the proof can give you valuable insights into what the theorem really means and how it might be used. Also, reading proofs made by other people can help you prove you own theorems and write them up coherently.