It is clear to me that this [his recent works and ideas on art] is art for the future. Futurism, although it has advanced beyond naturalism, occupies itself too much with human sensations. Cubism – which in its content is still too much concerned with earlier aesthetic products, and thus less rooted in its own time than Futurism – Cubism has taken a giant step in the direction of abstraction, and is in this respect of its own time and of the future. Thus in its content it is not modern, but in its effect it is.

In a letter to the Dutch art-critic and buyer of his paintings, H. P. Bremmer, Paris 29 January 1914; as quoted in Mondrian, - The Art of Destruction, Carel Blotkamp, Reaktion Books LTD. London 2001, p. 75