If all materials are equally valuable to the artist, it does not mean that they are all equally fit for all his purposes. Solidity and manufacturability demand materials that do not harmonize with the actual purpose of the building. Here the architect has the task of producing a warm, inhabitable room. Carpets are warm and inhabitable. So he decides to spread one of those on the floor and to hang up four carpets, which are to form the four walls. But you can’t build a house from carpets. Both the carpet on the floor and the tapestries on the walls demand a structural scaffolding that anchors them in the correct place. The invention of that scaffolding is only the architect’s second task.

That is the correct, logical path that architecture is taking. For that is the order in which humanity learned to build. In the beginning was cladding. Man sought shelter against the horrors of the weather, shelter and warmth as he slept. He sought to cover himself. The ceiling is the oldest architectural detail. Originally it consisted of animal hides or fabrics, a meaning preserved in the Germanic languages even today.¹² This ceiling had to be anchored somewhere, if it was to provide sufficient shelter for a family. Soon it was joined by the walls, to provide shelter from the sides as well. And in this sequence the idea of building developed both in humanity and in the individual.

There are architects who do that differently. Their imagination creates not spaces but wall sections. What the wall sections leave over are spaces. And for those spaces the type of cladding that is thought suitable for them is added afterwards. That is art accomplished empirically.

But the artist, the architect, first feels the effect that he is seeking to produce and then with his mind’s eye he sees the spaces that he wants to create. The effect that he wants to make on the viewer, whether it be fear or horror, as in a prison; the fear of God, as in a church; respect for the power of the state, as in a government building; piety, as in a funeral monument; homeliness, as in a residential house; congeniality, as in a drinking-hall: this effect is prompted by the material and by the form.

Every material has its own formal language, and no material can lay claim to the forms of another material for itself. Because forms have arisen out of the usability and mode of production of every material, they have developed with the material and out of the material. No material permits an intervention into its range of forms. Anyone who tries such a thing will be branded by the world as a forger. But art has nothing to do with forgery, with lies. The paths of art may be thorny, but they are clean.

The tower of St Stephen’s Cathedral could be cast in concrete and placed somewhere or other – but then it would not be a work of art. And what applies to the steeple of St Stephen’s also applies to the Palazzo Pitti, and what applies to the Palazzo Pitti also applies to the Palazzo Farnese. And with this building we would be right in the middle of our Ringstrasse architecture. A sad time for art, a sad time for the few artists among the architects of those times who were forced to prostitute their art for the sake of the rabble. Only a few were in the happy position of finding clients who thought grandly enough to allow the artist to carry on. The luckiest of these was probably Schmidt.¹³ He was followed by Hansen,¹⁴ who, if he felt out of sorts, sought comfort in terracotta building. Poor Ferstel¹⁵ must have endured terrible torments when he was forced at the last minute to nail on whole parts of the façade of his university in precast concrete. The other architects of the day, with a few exceptions, were free of such sickly sentimentality.

Are things different today? Allow me to answer that question. Imitation and surrogate art still prevail in architecture. More than that, in fact. Over the last few years a number of people have come forward to defend this trend – one of them anonymously, admittedly, since the issue struck him as a little ambiguous – so that the surrogate architect no longer needs to stand quietly aside. Now the construction is nailed with aplomb to the façade, and the stone upright is hung with artistic justification beneath the main cornice. Come, ye heralds of imitation, come ye manufacturers of mocked-up carvings, bodge your home windows and your papier mâché tankards! A new spring is dawning in Vienna, the soil is freshly manured.

But is a living room decorated entirely with tapestries not an imitation? The walls are not built of tapestries, after all. Certainly not. But those tapestries claim only to be tapestries and not bricks, they don’t want to be mistaken for bricks, they show that neither through their colour nor their pattern, but clearly reveal their significance as a cladding of the surface of the wall. They fulfil their purpose according to the principle of cladding.

As I mentioned at the outset, cladding is older than construction. The reasons for cladding are manifold. Firstly it is a protection against inclement weather, like an application of oil paint to wood, iron or stone; then it is for reasons of hygiene, such as glazed tiles in a lavatory to cover the surface of the wall; then it is the means to a particular effect, like the colourful painting of statues, the papering of walls, the veneering of wood. The principle of cladding, first declared by Semper, also extends to nature. Man is clad with a skin, the tree with bark.

But the principle of cladding also has its own particular law. No need for alarm. Laws, it is commonly said, bring all developments to an end. And besides, the old masters also managed perfectly well without laws. Of course. But where theft is unknown there would be little point in making laws to forbid it. When the materials used for cladding were not yet imitated, there was no need to work out laws. But now it seems to me to be high time.

So this law is as follows: the possibility of confusing the cladded material and the cladding shall be ruled out in every case. Applied to individual cases, this clause would read: wood may be painted with every colour, except one – wood colour. In a city whose Exhibition Commission decided to paint old wood in the Rotunda ‘like mahogany’, in which graining is the only painted decoration of wood, this is a very bold statement. There seem to be people hereabouts who find it elegant. It does not seem so to me. And neither do I find it beautiful. As railway and tramway carriages, like all forms of carriage, come from England, they are the only wooden objects that display absolute colours. I now dare to assert that I would rather see such a tramway carriage – particularly those from the electric line – in absolute colours than, following the beauty principle of the Exhibition Commission, if it were painted like mahogany.

But there is a true sense of elegance slumbering in our nation, albeit buried and hidden away. Otherwise the tram company would not be able to count on the fact that the brown-painted – wood-coloured – third class awakens less elegant feelings than the green first and second.

I once demonstrated this unconscious feeling to a colleague in a rather dramatic way. On the first floor of a building there were two apartments. The tenant of the first apartment had had the mullions and transoms, which were otherwise painted a grained brown, painted white. We had had a bet, whereby we would invite a certain number of people in front of the house and ask them, without drawing their attention to the difference in the mullions and transoms, on which side they thought Herr Blunzengruber lived and on which side Prince Liechtenstein, the two parties that we allowed ourselves to have renting the house. The wood-grained side was unanimously held to belong to Blunzengruber. Since then my colleague has only painted white.

Wood-graining is, of course, an invention of our century. In the Middle Ages wood was predominantly painted bright red, in the Renaissance blue, in the Baroque and the Rococo white for the inside, green for the outside. Our farmers have retained sound enough sense to paint in absolute colours. How charming in the countryside are the green gate and the green fence, the green shutters against the white, freshly painted wall. Unfortunately some villages have made our Exhibition Commission’s taste their own.

We might recall the moral outrage that arose in the surrogate applied arts camp when the first furniture painted with oil paint came from England to Vienna. It was not the painting that aroused the fury of those good citizens. Even in Vienna, as soon as soft wood had come into use, it had been painted with oil paint. But the fact that the English furniture dared to display its oil paint as frankly and freely, instead of imitating hard wood, really raised the hackles of these queer characters. They rolled their eyes and pretended never to have used oil paint. Presumably these gentlemen are of the opinion that their wood-grained furniture and buildings have hitherto been seen as hard wood.

If such observations in my outline of these painters prefer not to name names, I think I can be sure of the gratitude of the fraternity.

Applied to plasterers, the principle of cladding would read: stucco can be given any ornament but one – bare brickwork. We might imagine that there is no need to utter something so obvious, but it is only recently that my attention has been drawn to a building whose plastered wall was painted red and given white joints. That very popular kitchen decoration that imitates stone blocks falls under the same heading. And so all materials that serve to disguise walls – wallpaper, tarpaulin, fabrics and tapestries, tiles and stone blocks – should not be used for representation.

A cladding material can keep its natural colour if the covered material is the same colour. So I can paint black iron with tar, I can cover wood with a different wood (veneer, marquetry, etc.), without having to paint the covering wood; I can coat a metal with a different metal using fire or by galvanizing. But the principle of cladding forbids copying the material beneath with a coloured substance. Hence iron can be tarred, painted in oil paint or be galvanically coated but can never be hidden with bronze paint, in other words a metal paint.

Here it is worth mentioning chamotte¹⁶ and artificial stone plates, which on the one hand imitate terrace plaster (mosaic) and on the other Persian carpets. Certainly there will be people who believe it – the factories must know their clientele.

But no, you imitators and surrogate architects, you are making a mistake. The human soul is too elevated and sublime for you to dupe it with your little tricks and tactics. You have our pitiful bodies in your power. They have only five senses at their disposal to distinguish the authentic from the fake. And where man with his sensory organs is no longer enough, that is where your domain begins, that is your realm. But once again, you are mistaken. Paint your best inlays very, very high up on the ceiling, and our poor eyes will believe the lot. But the divine psyche does not believe your deceit. In the best-painted, ‘as if inlaid’ intarsias it senses only the oil paint.