In the Eternal Evidence, René Magritte portrays the idealised nude as an assemblage of body parts rather than a whole. Undeniably, at a distance it is still possible to read the image as a single subject; however, as one gets closer to the work the fragmentary nature of the object dominates the vision. The fragments are constructed by a gap that is composed of two distinct elements –the emptiness between the framed canvases that is suggestive of the missing parts of the painting, and the frame around the canvas which defines and articulates the part. The disposition of the canvases on the wall surface in their deliberate misalignment ensures that they appear as if they do not quite fit with each other. Magritte was known as an artist who ‘rendered thought visible’. I would like to suggest that in this particular piece of work, the design of the gap is as much a part of the painting as the fragments itself, and allows the provocations fundamental to his work to reveal themselves – the ideal nude as a set of perfectly formed parts that do not necessarily fit perfectly together.
Staring for an inordinately long time at a reproduced print of the Eternal Evidence in a book, the gap, as I call it, acquires a life of its own, detached from the very source of its conception, it becomes dominant in the way I begin to read things around me. I try to understand its role, not as a metaphorical or metaphysical concept but rather as a deliberate designed object. This forms the pretext for this paper where I argue that the gap is an act of design and rather than absence it is embedded with its own intelligent content, deployed in a collage-like technique, as an operative element used to challenge preconceptions, distort existing meaning and foster new relations between parts. The gap is essentially not an absence of content but rather through its absence generates content. This paper is only a start of an exploration and should be read in that manner – as an instrument through which this object, the gap, is being investigated, qualified and thus, rendered visible.
In the 1830s, Abel Blouet, an architect with considerable experience in prison design was invited to collaborate with Michael Faraday – the inventor – to design wall sections for the cell divisions in Millbank penitentiary.  A successful design, for the brief that they were given, would entail that prisoners would not be able to communicate with each other across the dividing walls between their cells. The project was based on the belief, prevalent in the early nineteenth century, that silence in the prison was an important quality that needed to be designed within the space to ‘fabricate virtue’ in the criminal mind. Criminality was considered an illness that could be cured in a space that fostered self-reflection, which was of course, best practiced in silence. Silence was translated into segregation: an act which would protect the criminal mind from ‘infectious thoughts’ that if left unchecked, would spread rapidly within an already contaminated community. In earlier versions of prisons designed in the same period and founded on similar reasoning, silence manifested itself as solitary confinement, which was proved to foster mental and social side effects; thus, forcing its rapid demise except in extenuating circumstances. Within that context, Blouet and Faraday interpreted their assignment not as a way to insulate the cell from all sound but rather, as a way to ensure that intelligible communication between the cells was scrambled, leading instead to a form of white noise. Some of their more successful experiments relied on a double wall with serrated interior voids and a sail cloth suspended within.
The most rudimentary experiment – a double wall with an air gap in between – was the least successful, in the sense, that while it dampened the volume of the information across the wall, it did not alter the message that was being transmitted and it could be easily bypassed by increasing the spoken volume. The serrated gap on the other hand, with its formal intelligence through distortion challenges the very idea of proximity, silence and communication.
While the prisons in the 19th century used the thickness of the wall in order to distort audible content; however, in the glass pavilion for the glass museum in Toledo designed by SANAA in 2002, the thickness of the wall becomes a device that questions the very attributes of glass and its purported transparency. Summarily the pavilion can be described, as a series of habitable and inhabitable spaces both unambiguously defined and limited by glass walls, which are assembled under a single horizontal plane. Beatriz Colomina describes the design act as: 
Most importantly what they are showing is the cut between them, the inaccessible space of the wall itself: you cannot enter that space: the double line of the wall undoes any sense of solidity. SANAA’s vision is far from Crystal clear, in fact the glass pavilion seems more like a blurring of the view, a softening of the focus, than about the transparency of the early European avant-garde.
Reimagining the plan of the pavilion to make visible what she identifies as the ‘inaccessible space of the wall’, the plan can be read in parallel to the painting by Magritte discussed above: the glass walls perform a similar role as the frames in the painting do; whereas, the ‘inaccessible space of the wall’ can be related to the emptiness between each of these frames. The gap – glass plus ‘inaccessible space of the wall’, or material plus form – performs numerous roles in the project: defines individual spaces, revealing the unexpected, multifarious attributes of glass and thus, questioning and challenging its idealisation, and lastly, exposing the gap itself as an operative apparatus within the design.
Moving away from the thickness of the wall towards the thickness of the ceiling we pause at Double Bind, an installation by Juan Muñoz, in the Turbine Hall in the Tate Modern in 2001 which, pays homage to the artist’s interest with the work of Gregory Bateson as evident in its title. The installation is a series of horizontal layers: the spectators walk along the sloping ramp in a tight horizontal volume of space controlled by a low ceiling pierced intermittently by vertical shafts, that allow the other layers of the installation to become knowable. Looking upwards into the shaft one becomes aware of two more layers: the first displays fragments of life animated by architectural elements and human figures, and the other is an inaccessible space just below the ceiling of the turbine hall, which is brightly lit and in effect, creates the conditions for being able to see the in-between space of life. The fragmented view of a life that is viewed but unknowable is compounded by the unusable elevators that traverse across the different layers of the installation.
The installation plays with the gap as device that reveals but, through this act, shows what is still concealed, which can be read as a way of making visible the concepts of impenetrability and limits even when they are known. Here I would read the gap not only as the shaft cut-outs which makes some things visible but rather as all the spaces that are in-between – the lighting sandwich as well as the spaces that are in between the shaft cut-outs as the gap through which the installation provokes the imagination and questions knowing itself.
Lastly, as a foil to the way that the gap has been discussed to far – an inaccessible device that aims to distort, challenge and reveal– I am going to present RPJ, an unbuilt Giulia Foscari project in collaboration with Office for Metropolitan Architecture and Metro architects in São Paulo which uses the gap as an un-programmed device, deliberately accessible and in fact suggestive of increasing penetration into the heart of the building. Foscari explains that the Lina Bo Bardi museum in São Paulo, the São Paulo Museum of Art (MASP), was an important reference for this design. In MASP, bo Bardi rips the mid-section of the building out and continues it with the street plane, consequently pushing part of the building under the ground and part as hovering above this constructed public space. This act should be read as different to the act of simply erasing the ground floor of the building, as it ambiguously stages the ownership of the public space between the city and the museum, in effect, forging joint ownership, a truly a public-public partnership. In addition, by programming the below and the above it forces the ‘public space’ to move from an external condition to one that is exterior but intimately connected with the circulation and activity of the museum.
In the high rise horizontal slab building proposed by Foscari et al, bo Bardi’s act is repeated multiple times across the section of the buildings. Each public terrace with its unique spatial organisation and topography would, inevitably affect the programmed space both below and above and in turn be affected by them. This act forces two different design logics on to the same building – programmatic organisation and spatial organisation, which is apparent in the diagrams. This collage-like technique of introducing a designed gap into a programmed space is not unique to this project and can be traced to other works by OMA, for example, the unbuilt Agadir convention centre, the unbuilt Très Grand Bibliothèque, to mention a few.
Conceptually the gap is not a single thing and it is deployed in different ways, as evident in the examples mentioned above: in the prison the gap, or absence of material is in fact is a double wall separated by a serrated air gap and this in effect reconstructs the notion of silence as something that is not necessarily the absence of noise; whereas, in the pavilion, the ‘wall thickness’ is a constructed inaccessible space between programmed spaces that forces a re-evaluation of the quality of transparency attributed to glass because of optics. The installation is essentially an act of selectively piercing horizontal layers to highlight the visible and the unknowable; on the other hand, the building uses the gap as a programming strategy to juxtapose two different design logics the planned but typically organised vis-à-vis the unplanned but modulated.
I started this paper by defining what I mean by a gap, which I read as designed absence that operationally functions in a collage-like manner: by recalibrating the relationships between itself and the rest of the work; by continuing a dialog with other projects in both the architectural discipline and across to other disciplines. ‘Mind the Gap!’ is a beginning and should be continued…
 Marcel Paquet, Magritte, (Taschen GMBH, 2000)
 Robin Evans, Fabrication of Virtue: English Prison Architecture 1750-1840, (Cambridge: Cambridge University Press, 1982). In this book Evans discusses the transformation of prisons and is important for the general understanding of the role of silence within the prison reformation. Evans has reused the factual information from his book to talk about the architecture for restricting information in a shorter essay ‘The Rights of Retreat and the Rites of Exclusion’ which can be found in his book Translation from Drawing to Building and other Essays, and it is in here that one would be able to also find the drawings for the wall section and more details about them.
 Beatriz Colomina, ‘Blurred Vision: Architectures of Surveillance from Mies to SANAA’, filmed January 2009 at the Architectural Association, School of Architecture, London, http://www.aaschool.ac.uk//VIDEO/lecture.php?ID=30
 ‘The Unilever Series: Juan Muñoz: Double Bind’, Tate Modern, http://www.tate.org.uk/whats-on/tate-modern/exhibition/unilever-series/unilever-series-juan-munoz-double-bind, <accessed 9 April 2018>. In addition, the website below is an article in the Spanish media, in Spanish: http://www.abc.es/cultura/arte/abci-double-bind-testamento-artistico-juan-munoz-exhibe-primera-espana-201710200148_noticia.html.