Thick Edge

Definition

The thick edge is Iain Borden's name for what a boundary is once it is treated socio-spatially rather than as an object or line: "The boundary is not a surface but a thick edge, a five metre deep in-between zone in which social relations are challenged and controlled through architectural materiality." The concept rests on two theses. First, via Simmel: "the boundary is not a spatial fact with sociological consequences but a sociological fact that is formed spatially" — boundaries "do not cause sociological effects in themselves, but are formed between social elements," their significance "springing from interaction on either side of the line." Second, via Lefebvre: spatiality is not "the simple relation between objects and forms" (Soja's "illusion of opacity") but a force, a flow, among social elements — so the edge is where that flow is negotiated rather than stopped. The Intimus editors' framing compresses it: boundaries are "permeable, temporal and political markers of bodily negotiation."

The edge's thickness is exercised through a series of body-centric devices, of which vision "is just one": at Holy Trinity, Kingsway, the low wall in front of the portico was "of the right depth and height to sit and, potentially, to sleep upon" — inhabitable edge-depth — until the Post Office's blue screen made "a sudden 45 degrees deviation… leaving only 150 millimetres clear in front," so that "the low wall becomes too shallow for a person to sleep upon." The edge's temporality matters equally: at Broadgate, the 'Go-Between Screens' are "not just the space but the lived time of several seconds through which the visitors validate themselves in relation to Broadgate. As a result, space, temporality, body and identity are mutually confronted and constructed." The thick edge is thus simultaneously material (depth, deviation, tactility), temporal (the seconds of passage), and political (who is "divorced from" the building, who is provoked to ask "'Should I be here, and now? Do I have the right of passage?'").

The concept is the wiki's boundaries cluster's fifth register — the socio-spatial one — and the urban-scale cousin of Teston's disciplinary frontier ("a liminal zone; it has thickness") and of poché's thickened zone: Borden's sitable low wall is inhabitable edge-depth, and the 45° deviation is its deliberate un-poché-ing. See space-of-flows, hostile-architecture, privatised-public-space.

Key Thinkers

• Iain Borden — the concept's author: the blue screen at Holy Trinity and the 'Go-Between Screens' at Broadgate as the two built demonstrations that the boundary is a zone of negotiation, not a surface.
• Georg Simmel — the philosophical ground: the boundary as "a sociological fact that is formed spatially," formed between social elements rather than causing effects.
• Henri Lefebvre — the spatial ontology: spatiality as force and flow among social elements ('second nature'), against the container-conception.
• Marc Augé — the temporal mechanism: the non-place's "turning back on the self" as what the passage through the edge does to identity.
• Mark Taylor & Julieanna Preston — the interior-design transmission: the Intimus framing that makes the thick edge the literal and theoretical threshold interior design must confront.

Related Concepts

• boundaries — the parent cluster: the thick edge is that concept's socio-spatial register (after Ardener's rules, Taylor's actuated/automated registers, Beecher's moved screen, Manack's disclosed gap).
• space-of-flows — the spatial ontology the thick edge presupposes: architecture as "the interrelation between things, spaces, individuals and ideas."
• hostile-architecture — the edge's dark technique: edge-hardening (the 45° deviation, spiked sills, sprinklers) as the deliberate destruction of inhabitable edge-depth.
• privatised-public-space — the political habitat of the thick edge: Broadgate's "spaces at once public and private" whose gates provoke self-policing.
• poche — thickness in the wall vs thickness at the edge: the sitable wall as urban, inhabitable depth; the deviation as engineered emptiness.
• disciplinary-frontiers — the thickness metaphor at the scale of knowledge domains: "it has thickness. We often assume there is a hard line… but in reality the defined edge is imaginary."
• non-places — the gate-passage as non-place: "a turning back on the self," "only solitude, and similitude."
• embodiment — the body as design parameter: exclusion computed from "the thickness of the human body"; tactility (Merleau-Ponty) subtracted from the edge.
• panopticon — the Benthamite project's terminal extension: each citizen surveys and disciplines themselves in the seconds of passage.
• inside-outside-dialectic — the in-between zone as the lived depth of the inside/outside division at urban scale.
• enclosure — the exclusionary pole of the edge: "clear blue water between spaces and peoples."
• right-to-the-city — the political question the edge poses in passing: "Do I have the right of passage?"

Source Support

Sources in the wiki that discuss this concept:

• Thick Edge (Borden 1996/2006) — the founding source: the blue screen's 45° deviation and 150 mm body-clearance (pp. 51), the "five metre deep in-between zone" definition (p. 51), the 'Go-Between Screens' that are "never sealed" and the "lived time of several seconds" of self-validation (pp. 52–54), and the Simmel/Lefebvre/Augé theoretical apparatus.
• Inside Looking In: The Prospect of the Aspect (McClure & McClure 2018) — the prospect-framing register: thresholds that do not stop but direct the edge's negotiation — the Pantheon's colonnaded porch as "a liminal boundary to the plaza" that continues the spatial recursion outward, Säynätsalo's heavy masonry threshold opening into "the thin, yet simultaneously expansive, threshold" of the exterior room, and the Pompidou's escalator tubes where "the overtly bracketed 'interior' space offers the prospect of the aspect to the strata of the surrounding context." Where Borden's edge measures the body in passage, the McClures' edges "frame the prospect horizontally and vertically" — thickness as the condition's amplifier rather than its containment. See prospect-of-the-aspect.
• The waiting room (Hedges 2018) — the interior instance this page's open question asked for: the waiting room is the thick edge indoors — "a semi-private transition to the fully public space of the concourse, an upholstered, paneled haven… a place for waiting and a peculiar limbo used before or after travel," "a threshold between stasis and movement," where "a transient population is viewed from the dark interior through to the bright light of the concourse, neither fully public nor fully private." Borden's edge is crossed in seconds; Hedges's is dwelt in — the in-between zone given furniture (rows of seats), duration (the clock, the timetable), rules ("etiquettes and excluding boundaries"), and its own temporality ("an interstitial period"). See waiting-room, liminality, temporality.
• source-notes/edelman-2006-mens-room

Open Questions

• Does the thick edge have an interior instance — the vestibule, the lobby threshold, the door-swing zone — or is it constitutively urban (a relation between building and street)? Hedges's waiting room now supplies the interior case: a room-scale in-between zone, dwelt rather than crossed ("a peculiar limbo used before or after travel"). The distinction may be temporal: the edge's "lived time of several seconds" (Borden) vs the waiting room's interstitial period — can thickness be measured in durations as well as metres?
• The blue screen produced exclusion by subtracting depth (150 mm) and tactility; the Go-Between Screens produced control by leaving a 2-metre gap. Is there a design vocabulary for the hospitable thick edge — depth that invites lingering, sitting, sleeping — and what political conditions let it survive its owners?
• Borden's edge is "a projection outward by visitors" (the Sartrean look returned). Does that relieve the designer of responsibility for the edge's social effects, or relocate responsibility to the point where the body-parameter (the 150 mm) is drawn?
• Is the edge's "lived time of several seconds" designable — and is it the same temporality the Intimus dressing-table niche shelters (interiority at the threshold), or its public opposite?