It should be understood that this argument is directed at the whole of mathematical knowledge, and it is not framed for a single formal system or language. Many attempts to provide a foundation for mathematics in such a language manage to reduce assumptions in that formal system or language. What has been done in such a case is to push some or all of the basic assumptions into the meta-language, as was the formalists explicit strategy. Wherever it remains, and somewhere it must, there is a kernel of assumptions which introduces truth into the system, and which deduction transmits to all the theorems of the system ( provided the system is safe, i.e., consistent).