Since all preceding schools of painting have proved that the spirit of beauty does not lie in nature but in the 'I', now that painting in all its var… - Theo van Doesburg

White
This is the spiritual colour of our times, the clearness which directs all our actions. It is neither grey nor ivory white, but pure white.
White This is the colour of modern times, the colour which dissipates a whole era; our era is one of perfection, purity and certitude.
White It includes everything. We have superseded both the 'brown' of decadence and classicism and the 'blue' of divisionism, the cult of the blue sky, the gods with green beards and the spectrum.
White pure white...

Quite possibly this aesthetic contemplation coincides with religious feeling or with the uplift of the religious spirit, since in a work of art it is the deepest inwardness that expresses itself. It is necessary however, to bear in mind the essential distinction that the contemplation or uplift in art – i. e., the experience of pure art – contains nothing dreamy or vague. It is exactly the contrary; true artistic experience is altogether real and conscious

We speak of concrete and not abstract painting because nothing is more concrete, more real than a line, a colour, a surface. [quote of Van Doesburg, c. 1925]