 Unfortunately — and perhaps inevitably, in the face of opposition from mathematicians of such stature as Hilbert — Brouwer’s intuitionist school of mathematics and philosophy became more and more involved in what, at least to classical mathematicians, appeared to be quasi-mystical speculation about the nature of constructive thought, to the detriment of the practice of constructive mathematics itself. This unfortunate polarisation between the Brouwerians and the Hilbertians culminated in the notorious Grundlagenstreit of the 1920s, details of which can be found in the Brouwer biographies by van Dalen [1999, 2005] and van Stigt [1990].