Stylistic Unity

Definition

Stylistic unity is the design-reform principle that one style of furnishing and decoration should govern the whole house, against the convention that each room may carry its own. Its founding statement is Eastlake's closing prescription (1868): "Choose what style of furniture we may, it should surely be adopted throughout the house we live in" (p. 102). The principle is negative in origin — an attack on room-to-room difference "in both form and style" (editors' headnote), i.e., on the practice of furnishing the dining room as oak-and-flock-paper, the drawing room as walnut-and-green-gold, and the mansion's apartments "each after a style of its own. Thus we had Gothic halls, Elizabethan chambers, Louis Quatorze drawing-rooms, &c., &c., all under one roof," a system Eastlake calls "absurd and mischievous in its effect upon uneducated taste" and "the practical evidence that a healthy and genuine taste was altogether wanting" (p. 102). The Intimus editors read the agenda forward: "In an effort to homogenise the interior, Eastlake sets a clear agenda by questioning conventional arrangements that seek room-to-room difference in both form and style" (editorial headnote). The concept's crucial internal distinction is Eastlake's own: variation grounded in use is legitimate (the dining-room sideboard solid "on account of the use to which they are put"; lighter chairs for reception rooms), variation grounded in style is not ("though the shape of a cheffonier may differ from that of a buffet, there can be no reason whatever why the style of design in these respective articles of furniture should vary," p. 102). Stylistic unity is thus a program of disciplined difference, not uniformity of furniture.

Key Thinkers

Charles L. Eastlake — the concept's author (1868): the house-wide style as the reform remedy for trade-governed room-codes; the use/style distinction as the principle's edge.
Mark Taylor & Julieanna Preston — the editors who name the agenda "homogenisation" and canonize the excerpt as the interior's programmatic text (2006).
Elsie de Wolfe — the partial counterpoint (1913): her anti-periodism ("Don't go about the furnishing of your house with the idea that you must select the furniture of some one period and stick to that") accepts Eastlake's attack on trade codes while refusing the single-style demand — unity through harmonized comparison of qualities ("Lines and fabrics and woods are the things to be compared"), not through one adopted style.
Christopher Dresser — the reform predecessor's methodological kin: repose achieved through harmony of effect — the systemic, room-coordinated regime of decoration that unity principles presuppose.
Edith Wharton & Ogden Codman Jr — the principle's architectural statement and its rationale (1898/2006): "It is this which makes it important that each room (or, better still, all the rooms) in a house should receive the same style of decoration" — unity grounded not in piety but in the replaceability-corollary of the double test (appropriateness), and defended against the objection that it is "as meaningless a piece of archaism as the habit of using obsolete fragments of planning or decoration… but such is not the case" (p. 388). Their mixed-style proof supplies the principle's physical argument: "the massive dimensions and heavy panelling of a seventeenth-century room would dwarf a set of eighteenth-century furniture; and the wavy, capricious movement of Louis XV decoration would make the austere yet delicate lines of Adam furniture look stiff and mean" (p. 389) — the mismatched ensemble is deformed, not merely inelegant.

fashion — what unity is meant to defeat: the cyclical, trade-driven "fashion of taste" (rosewood → mahogany → walnut) whose rules change "from age to age" without rational ground (p. 101).
style — the concept's currency: unity is a thesis about how style is held (house-wide) rather than what style is; it presumes style is chooseable ("Choose what style of furniture we may").
taste — the faculty the program claims to serve: "healthy and genuine taste was altogether wanting" (p. 102) when rooms obey codes; conformity is mistaken for taste.
domestic-interior — the territory of the program: the house as one designed field rather than a collection of separately coded rooms.
design-reform — the movement-context: unity as the reform polemic's constructive demand, paired with the attack on trade convention and the "degradation of decorative art."

Source Support

Sources in the wiki that discuss this concept:

The Historical Tradition (Wharton & Codman 1898/2006) — the principle's architectural rationale and its physical proof: "It is this which makes it important that each room (or, better still, all the rooms) in a house should receive the same style of decoration. To some people this may seem as meaningless a piece of archaism as the habit of using obsolete fragments of planning or decoration; but such is not the case" (p. 388) — unity derived from the double test's appropriateness, not from period-piety; the form-over-color grounding ("it is the feeling for form, and not any archaeological affectation, which makes the best decorators insist upon the necessity of keeping to the same style of furniture and decoration," p. 389); the mixed-style incompatibility (seventeenth-century panelling dwarfing eighteenth-century furniture; Louis XV waves making Adam furniture "look stiff and mean," p. 389); and the escalation: "Many persons object not only to any attempt at uniformity of style, but to the use of any recognized style in the decoration of a room. They characterize it, according to their individual views, as 'servile,' 'formal,' or 'pretentious'" — answered by the taxes-and-grammar defense (p. 389) and by the historical counter-evidence that the private rooms of 1650–1800 "were far simpler, less pretentious and more practical in treatment than those in the average modern house" (p. 390). Where Eastlake's unity is a furniture prescription and the Garretts' a professional aim, Wharton & Codman's is a consequence of proportion: "a room, whatever its decoration may be, must represent the style to which its proportions belong" (p. 388).
Ultrasuede (Wagner 2002/2006) — the concept's postwar-North-American form and its critical inversion. Wagner's opening names aesthetic unity as modernism's scale-device: the instrumental vision 'panned easily from the piece of furniture to the design of the city, and to have done so by subjecting diverse scales to the binding operations of aesthetic unity' (p. 380) — stylistic unity as an urban-operative, not just a room-operative, convention (the Eastlake house-wide agenda raised to the city). The price is disciplinary: 'This unity came at the price of the autonomy of the individual design disciplines, which were silenced by the ambitions and economic imperatives of larger orchestrations' (p. 380). Wagner's evidence is also the concept's most literal built vocabulary: the 'discordant collection of table and chair legs' erased by unified pedestal bases (the 'slum of legs,' p. 380–381), and interiors whose 'enveloping continuity of the whole and its governing surfaces subsumed and refigured the parts' (p. 380). Where Eastlake's unity was a reform from within decorating, Wagner's is orchestration from architecture above — the concept's two political directions.
The Dining Room (Eastlake 1868/2006) — the primary source: the fallacy of room-bound decorative art (p. 101); the use/style distinction (cheffonier/buffet, p. 102); the two-extremes argument ("a solid, gloomy, and often cumbersome class of furniture below… a flimsy and extravagant one above… they cannot both be right," p. 102); the multi-style mansion as the disease (p. 102); the unifying prescription (p. 102); the editors' "homogenise the interior" framing (headnote).
'Decorators May be Compared to Doctors' (Ferry 2003/2006) — the principle's professional statement and its positive form (1876): the Garretts define their 'house decorator' as the professional "able to judge both the total effect and the minute details of the decorative scheme, and who aims to create a 'harmonious whole'" (Ferry, pp. 114–115) — unity re-described as the professional's aim rather than the reader's duty, the whole-house coherence Eastlake demanded now the house decorator's competence. Where Eastlake's unity is negative (against room-codes), the Garretts' is constructive: the ordinary London house redecorated room by room (dining room, drawing room) into a single "Queen Anne" scheme (see queen-anne-style). The principle's succession: Eastlake prescribes unity (1868) → the Garretts practice it as a profession (1876) → de Wolfe replaces it with harmonized comparison (1913). See house-decorator, design-reform.

Open Questions

Is a house-wide style a principle or a new convention? Eastlake refutes the room-codes as arbitrary, but "it should surely be adopted throughout the house" installs a house-wide code — what distinguishes principled uniformity from just another "wholesome doctrine" delivered by a new authority?
Unity against free play: de Wolfe's decorator (1913) compares lines, fabrics and woods across periods — is comparative eclecticism the fulfilment of unity (harmony as the achieved relation) or its abandonment (the multi-style mansion defended)? Eastlake's "Gothic halls, Elizabethan chambers" target suggests the latter; de Wolfe's harmonized mixing suggests the former. The tension is unresolved in the wiki's sources.
Does homogenization have a gendered target? The rooms Eastlake satirizes — the "green and gold-papered drawing-room," the "vulgarity of garlands and bouquets" — are the feminine-coded ones; is the interior's unification a discipline of the decorative practices assigned to women (see gender-and-the-interior, the-decorative)?

Notes

Terminological caution: not to be confused with Heller's sociological homogenization (absorption into a homogeneous sphere of objectivation in the theory of everyday life) — the words share a root but name different concepts; this page is the interior-design sense (uniform style across a house's rooms) named in the Intimus editors' headnote.
This is the concept page the dining-room and drawing-room room-type pages are organized against: those pages document the room-codes; this page documents the attack on them.