What is a cathedral? Undoubtedly, most people think first of the French Gothic cathedrals: Notre-Dame in Paris, Chartres or Reims. For many, 'cathedral' is synonymous with 'Gothic,' and logically 'Gothic' is first and foremost 'cathedral Gothic.' This view is bound up with mental images of extremely rich and finely decorative architecture, with interiors comprising pillars, arches, stained-glass windows, and rib vaults, and exteriors characterized by exposed buttressing and pointed pinnacles and gables. The motifs that recur everywhere are the pointed arch, the rounded shaft and tracery.
In their construction, the Gothic cathedrals are mere frameworks, in comparison to the massive stone-wall heaviness typical of the preceding Romanesque style. They represent, from a technical viewpoint, bold, at times risky architectural engineering, in which the wall fabric is reduced to what is strictly necessary; this gives an impression almost of weightlessness, as if the laws of gravity, bearing and load in some inexplicable and miraculous way, do not apply here. This not only makes the building as light as it can be, but sometimes even gives the impression of a titanic upward surge.
Perhaps the most profound impression we receive from cathedrals in their original condition, like Chartres, is the surreal power of the illumination, from the coloured beams emanating through glass windows that twinkle like precious stones; these are surely intended to give the observer an idea of the splendour of the light of heaven, the divine light.
The architectural structure and the windows together create an aura that has something mysterious and numinous about it, and is also an expression of the transcendental. Thus, even today's cultivated visitors detect with the same powerful immediacy as the Romantics before them, when they rediscovered the Gothic cathedrals and praised them in hymns, that this is the house of God. It is a holy place, to which reverence is due. Never before or after has the vision of sacredness so magically affected the mind.
Step by step the cathedral becomes a towering house of glass with fragile, thinly partitioned lattices; at this point the High Gothic cathedral looks like an enormously oversized shrine. The epitome of this is the high choir of the cathedral in Cologne, ideally represented in the cross-sectional drawings of the early 19th century form the engravings of Sulpiz Boisserée. This is, perhaps, the most accurate reproduction of a cathedral ever, because it captures not only the building and its typical Gothic cathedral construction, but also the spiritual soul, indeed the very idea of the cathedral. Here, we can see what every Gothic cathedral really is: a phenomenal achievement, aways overwhelming, and never quite attainable.