Gradually I became aware [c. 1914-1918] that Cubism did not accept the logical consequences of its own discoveries; it was not developing abstraction… - Piet Mondrian

A form must be of its own time if it is to be recognized: one cannot relate to what one is not or does not have – Thus all that is of the past is to be rejected.

For the present at least I shall restrict my work to the ordinary world of the senses, since that is the world in which we still live. But nevertheless art even now form a transition to the finer regions, which perhaps I am incorrect in calling spiritual, for everything that has form is not yet spiritual, as I read somewhere. But it is nonetheless the path of ascension away from matter. Well dear Querido, with many heartfelt wishes, Piet Mondriaan.

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.