“…The theory of numerical fields has played an important role in drafting the Grundlagen. Very few researches have highlighted this point, but recent studies, after publication of Hilbert's geometry lectures [22], have shown that one of Grundlagen main aims was the introduction of number in geometry from inside and not from outside through an artificial Cartesian reference system [1,3,20]. The analytical method, thanks to the certainty of its results, had gradually subordinated synthetic geometry to algebra, imposing very demanding hypotheses on the idea of space, in particular continuity and derivability.…”