There's a Palladio show in the Royal Academy which offers a real insight into the conception of architectural space that has informed so much of our sense of the logic of buildings. When I entered the first room and saw the series of impressive models that accompanied the drawings, I immediately started thinking about sculptural space rather than building space and I imagined a bronze (don't know why) cube about 4 ft in its dimensions. 

How do you apprehend this object? In terms of volume? Am I aware of the air inside this cube and does this awareness govern my sense of the object? Or is it the weight and fact of its mass which will be revealed as much by the nature of the material used to contain this volume? This weight is never a straightforward or proportional link with the material used however, positioning, attitude and interaction with other spaces will govern that as much as the bronze - not so much what it is- more a case of what it is not.

Then there is the surface of the cube; is this uniform or irregular in facture? making the surface is thus "manufacturing". The surface can clothe or reveal the form and therefore communicate the nature of the volume of space enclosed too.

We see a bust of a head, yet suspend our take on the volume - it becomes a real head which is seen as we see a person. When you speak and look at someone you never think of their head as a sort of container and likewise look at a bust of a head and that sense of volume is absent; the form of the head, its nuances of modelling , carving, assembling - the palpable factors which determine the weight, mass and surface texture and are all explored eagerly by our eyes. (Maybe we simply apprehend physical features differently to physical space).

Returning to the Palladio exhibition. It was interesting to see how some of the masses were created. Large slabs built up over brick and render forms. Facades created by this clothing of form. A fearless demolition of the  - perceived - integrity of the process of building, which had more to do with a stage set than a living building.. maybe? yet these buildings work and command our attention through their cool collectedness. We talk of Palladian architecture and imply a "classical' , "symmetrical rightness" and order. A logic that is Appolinian. We don't look at the building or any building in the way we would that bust of a head. It is space not surface that takes the centre stage. Try looking around grander buildings and see what you really do "see". Can one sense the volume as much as the mass? Can you tell when there is cladding? Does it matter? Do the ends justify the means?

The integrity of the materials seems to be a major concern of artists and architects but more often than not the breakthroughs happen when this is in someway challenged: Cubism's papier colles, Matisse's sometimes flip between African and "Italian" spaces. I remember also being confused (or maybe bemused) at seeing one of his large ceramic murals translated from a giant cut out, and a couple of the tiles being in light relief - corrugating their way off and back onto the wall. They seemed to be sticking two fingers up to the visual language of the rest - and this is coming from the artist who talked of the 'purity of the means'.

The simple bronze cube vanished from my mind and any rules that I searched for went with it. Everything can make sense to a point, beyond that is a place in which the joker well as the genius operate. 

It can sometimes take a while to figure out who is who though.