Editing Pre-intuitionism (section)

==Other pre-intuitionists==
The above examples only include the works of [[Henri Poincaré|Poincaré]], and yet [[Luitzen Egbertus Jan Brouwer|Brouwer]] named other mathematicians as Pre-Intuitionists too; [[Émile Borel|Borel]] and [[Henri Lebesgue|Lebesgue]]. Other mathematicians such as [[Hermann Weyl]] (who eventually became disenchanted with intuitionism, feeling that it places excessive strictures on mathematical progress) and [[Leopold Kronecker]] also played a role—though they are not cited by Brouwer in his definitive speech.

In fact Kronecker might be the most famous of the Pre-Intuitionists for his singular and oft quoted phrase, "God made the natural numbers; all else is the work of man."

Kronecker goes in almost the opposite direction from Poincaré, believing in the natural numbers but not the law of the excluded middle. He was the first mathematician to express doubt on [[nonconstructive proof|non-constructive]] [[existence theorem|existence proofs]] that state that something must exist because it can be shown that it is "impossible" for it not to.