This Sentence is Wrong

The great Viennese logician Kurt Gödel studied statements which refer to themselves - and his results shook the foundations of mathematics. "All Cretans are liars", said Epimenides, a Cretan. But this means that his statement must be a lie too. But then it is false that Cretans are liars and the statement must be true. So what now? - Sentences which say something about themselves can lead to paradoxes. The mathematician and logician Kurt Gödel found ways to study such statements using the tools of modern logic, which made him one the founders of metamathematics - a branch of mathematics that does not try to come up with new proofs or calculations, but in a way investigates mathematics itself. It is mathematics trying to figure out what can be figured out with mathematics.