With the proof of the Poincare conjecture, it's a great time to look at the whole of 3-manifold theory and poke at it. Some things are "more proven" than others. For example: We only have one proof of the Poincare conjecture. Similarly, there's only one proof of the Smale conjecture. Some things are "super proven", like Dehn's Lemma, the Loop Theorem and the Sphere Theorem -- there's even more than one proof of their equivariant versions.