David Hilbert and Deutsch in den Wissenschaften

David Hilbert was probably one of the most, if not the most, prominent German mathematician. His interests ranged from quantum mechanics to topology, and notably from the foundations to the history of science and mathematics. Among his main interests there was geometry, at which he excelled by formalizing a two and a half centuries (Euclidian) geometry synthesizing it into a few (consistent and independent) different sets axioms, making the entire theory as mathematically precise as possible (in the tradition of Euclid himself but taken to culmination) at the level of precision that any theorem could from then on be carried out by a mechanical procedure manipulating symbols with no semantics attached.

His formalization of geometry certainly led him to think that math could one day be entirely formalized in the same way, proving any true theorem for a given mathematical theory. In his famous 1900 lecture at the Sorbonne in Paris Hilbert set most of the mathematics agenda for the 20th. century, and among the open problems there was the one he called the Entscheidungsproblem (the Decision problem), that is whether a mechanical treatment of math would eventually make possible theorems to be automatically proven.

In his address to the Society of German Scientists and Physicians, in Königsberg on September 8, 1930, Hilbert finished his speech with a loud “Wir müssen wissen — wir werden wissen!” (We must know — we will know!) (the radio broadcast was recorded and is available here and an English transcription here). His statement defined so well his mind that it was used as the epitaph on his tomb in Göttingen.

Hilbert’s ideas eventually led two mathematicians to make two of the greatest discoveries in the last century solving Hilbert’s open question in the negative with remarkable outcomes. First, there was Kurt Gödel, who in 1931 found that there are always (true) theorems in any (powerful enough) mathematical theory which these theories could never prove to be true (or false) calling them undecidable propositions. Then, Alan Turing in 1939, proved what he called the undecidability of the Halting problem for any general-purpose mechanical machine, with nothing else but what was the basis of the first description of the modern digital computer and the foundations of a new science: computer science.

Hilbert’s “Wir müssen wissen — wir werden wissen!” made all this possible, and its impact is yet to be measured in the centuries to come.

My entry to the Deutsch in den Wissenschaften Competition (German in the Sciences) organized by the Goethe Institut.

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