Writing about style in architecture, the nineteenth-century theorist Viollet-le-Duc asserted that "style consists in distinction of form," and complained that animals expressed this better than the human species. He felt that his contemporaries had "become strangers to those elemental and simple ideas of truth which lead architects to give style to their designs," and he found it "necessary to define the constituent elements of style, and, in doing so, to carefully avoid those equivocations, those high-sounding but senseless phrases, which have been repeated with all that profound respect which most people profess for that which they do not understand."
During the sixteenth and seventeenth centuries architects not only paid attention to internal arrangements, but subordinated the designs for the exterior to them. The usages of life dictated the arrangement and the arrangement suggested the form of the building. This was the dominant principle in times of Classical Antiquity and the Middle Ages.
Ruskin's Seven Lamps of Architecture provided seven guides, or 'lamps', for the troubled craftsman, guides for anyone who works directly on material things. These seven are:
The lamp of sacrifice: The willingness to do something well for its own sake.
The lamp of truth: The truth that 'breaks and rents continually'; Ruskin's embrace of difficulty, resistance, and ambiguity.
The lamp of power: Tempered power, guided standards other than blind will.
The lamp of beauty: Which for Ruskin is found more in the detail, the ornament—hand-sized beauty—than in the large design.
The lamp of life: Life equating with struggle and energy, death with deadly perfection.
The lamp of memory: The guidance provided by the time before machinery ruled.
The lamp of obedience: Obedience to the example set by a master's practice rather than by his particular works; otherwise put, strive to be like Stradivari but do not seek to copy his particular violins.