1 Kronecker, the semi-intuitionists, Poincaré -- 1.1 Introduction -- 1.2 Kronecker -- 1.3 The French semi-intuitionists -- 1.4 Poincaré -- 1.5 Conclusion -- 2 The genesis of Brouwer's intuitionism -- 2.1 Introduction -- 2.2 The early years -- 2.3 The first act of intuitionism -- 2.4 Topology -- 2.5 Intuitionism and formalism -- 2.6 The second act of intuitionism -- 2.7 The Brouwer lectures -- 2.8 The Mathematische Annalen and afterwards -- 2.9 Brouwer's personality -- 2.10 Conclusion -- 3 Overview of the foundational debate -- 3.1 Introduction -- 3.2 Quantitative inquiry -- 3.3 Qualitative inquiry -- 3.4 Conclusion -- 4 Reactions: existence and constructivity -- 4.1 Introduction -- 4.2 The beginning of the debate -- 4.3 The debate widened -- 4.4 Later reactions -- 4.5 Conclusion -- 5 Reactions: logic and the excluded middle -- 5.1 Introduction -- 5.2 The beginning of the debate -- 5.3 The debate widened -- 5.4 Later reactions -- 5.5 Conclusion -- 6 The foundational crisis in its context -- 6.1 Introduction -- 6.2 Metaphors -- 6.3 Philosophy -- 6.4 Physics -- 6.5 Art -- 6.6 Politics -- 6.7 Moderne and Gegenmoderne -- 6.8 Conclusion -- Conclusion -- A Chronology of the debate -- B Public reactions to Brouwer's intuitionism -- C Logical notations -- Dankwoord/ Acknowledgements.