Space and Form
Dieter Vandoren, 2012
"True art thus unfurls space, it creates space."
Such is the conclusion of Dick Raaijmakers' essay The great plane. 
But how is it that art can create space? What kind of space is that?
Is it a Cartesian 3-dimensional space in which physical objects are located in relation to each other? No. Art doesn't create extra volumes of 3D space. Quite to the contrary, art and other human activities create lots of things that tend to fill up 3D space. It 's technology's main drive, according to Raaijmakers.
The space we're talking about is mental space. The space composited of all of our perceptions and thoughts at the current instant and all of the recollections of previous instants. All of these aggregate in a subjective mental model of the world we live in. This model has many dimensions, from concrete sizes and colors to abstract moral and political ideas. It is also in constant flux. New perceptions and thoughts occur all the time. Past ones are forgotten and brought back to attention.
In short: space is composited by the dimensions of the individual's mental model of the world.
Art acts in this space. A good artwork opens up (unfurls) new dimensions in the observer's mind. New perceptions, thoughts, ideas, relations modifying or extending the observer's mental model of the world.
What then constitutes this art? It comes in many formats, tangible (painting) and intangible (poetry), which relate to the concrete and abstract dimensions of mental space. Prior to the production of the artwork, the artist maps a mental sub-space. It is the artist's ideal model encompassing all the dimensions deemed essential to the work (consciously as well as unconsciously). It doesn't have a specific form yet though. It only specifies the space in which the resulting form will eventually be created. Raaijmakers calls it a field. 
This field can be navigated and explored by sketching, improvising, experimenting within the chosen set of dimensions. By doing so the artist studies the possible concrete forms the work can take and ultimately picks the one(s) which reflect his intentions the best. (Raaijmakers invokes the image of the music composer taking walks through his chosen sound field, writing down his favorite routes as scores to be followed by the performing musicians, in turn leading the passive audience through the intended composition.)
The resulting form is constructed of a specific set of coordinates in the artist's mental space. It is then realized as a projection of that mental construct in the perceivable world, the actual artwork. The artwork 'works' if the perception of it opens up new dimensions in the observer's mind (not necessarily equal to the dimensions in the artist's mind). Art thus creates space.
 Arjen Mulder, Joke Brouwer eds., Dick Raaymakers: A Monograph, p.19, 2007, V2_/NAi Uitgevers
 Dick Raaijmakers, Cahier "M", A Brief Morphology of Electric Sound, p.49, 2000, Leuven University Press