Architects will usually answer "Architecture!"--and they're probably right. Architecture combines all the other media--painting, music, literature, dance, sculpture, and applies the disciplines of mathematics and geometry and engineering to propose spatial demonstrations of human habitation, except for the things we do "outside"--though, even there, landscape architecture and biology and geology and astronomy all have something to tell us about the purposes and possibilities of our being and occupying space, in whatever setting.
Loos's designs display the hallmark characteristics of high Modernism: Flat roofs, understated trim, unadorned window sashes, boxy rectilinear volumes, sharp edges, open planning facilitated with thin steel supports and trusses, lightness, flat unelaborated surfaces.
The Wittgenstein House was a laboratory for living. For some, though, it was an experiment that didn't work. Wittgenstein's sister, Hermine, wrote: "Even though I admired the house very much, I always knew that I neither wanted to, nor could, live in it myself. It seemed indeed to be much more a dwelling for the gods than for a small mortal like me, and at first I even had to overcome a faint inner opposition to this 'house embodied logic' as I called it, to this perfection and monumentality."
It was just as well, then, that Hermine didn't live there. But Wittgenstein's other sister, Gretl, did - both before and after the Nazi Anschluss - and apparently found it fitted her austere temperament perfectly. She and Viennese architect Paul Engelmann had invited Ludwig to collaborate with Engelmann on the design of her new house. Gretl did not issue the invitation lightly: she was no philistine and indeed, like the rest of the Wittgenstein family, was immersed in the world of arts (when she married in 1905, for instance, Gustav Klimt painted her portrait; Ravel wrote Concerto for the Left Hand for her brother Paul, a great pianist who lost an arm during the first world war).
At the time of the commission, Wittgenstein was at one of the many fraught transitional stages that pitted his life. He was fighting against depression and struggling to find a vocation worthy of his genius. He had abandoned philo-sophy in 1918, believing (wrongly) that he had solved all its problems with his Tractatus Logico- Philosophicus, whose ideas he had developed while serving as a soldier and later as a prisoner of war.
After the first world war, Wittgenstein had rid himself of his vast inherited fortune (his father had been a wealthy Viennese industrialist), sharing it among his brother and sisters. And, while philosophers around the world were realising that the Tractatus was the work of a genius, Wittgenstein became a primary school teacher in Trattenbach, in remote rural Austria. But after a classroom incident (the highly-strung Wittgenstein hit a pupil so hard the boy passed out), he quit. In despair, he contemplated becoming a monk - but instead took up gardening at a monastery.
But it couldn't last. There had to be some outlet for his visionary spirit. So the commission to work on his sister's house came at an opportune moment.
We can best understand Wittgenstein's architecture by seeing it as an extrapolation from the Tractatus. There Wittgenstein wrote that his philosophy was disposable: "My propositions are elucidatory in this way: he who understands me finally recognises them as senseless, when he has climbed out through them, on them, over them. (He must so to speak throw away the ladder after he climbed up on it)...Whereof one cannot speak, thereof one must be silent."
For Wittgenstein, it was precisely the most important things - God, ethics, aesthetics - that could not be put into words. They could not be said, only shown. Wilson writes: "It was as if Wittgenstein's first attempt to deal with his predicament after the ladder had been thrown away was instinctively to make things (architecture, sculpture, photography) whose essence is that they cannot be 'said' but must be 'shown'."
The philosopher's work on the house focused on the design of windows, doors, window-locks and radiators. "This is not so marginal as it may at first appear, for it is precisely these details that lend what is otherwise a rather plain, even ugly house its distinctive beauty."
Wittgenstein spent much time on these details. He took a year to design the door handles, and another year to design the radiators. Instead of curtains, each window was shaded by metal screens each weighing about 150kg, but easily moved by a pulley system designed by Wittgenstein. Bernhard Leitner, author of The Architecture of Ludwig Wittgenstein, hailed this "aesthetic of weightlessness": "There is barely anything comparable in the history of interior design. It is as ingenious as it is expensive. A metal curtain that could be lowered into the floor."
When the house was nearly complete, he insisted that a ceiling be raised 30mm so that the proportions he wanted (3:1, 3:2, 2:1) were perfectly executed. "Tell me," asked a locksmith, "does a millimetre here or there really matter to you?" "Yes!" roared Wittgenstein."
When we came to design our own house in 1991, I played with a number of these post-Modern design ideas, in working together with the firm which executed the plans. "Turning its back on the street" was one such idea; "ignoring the view" was another. The privilege to build a house--to one's own specifications--is an exercise which provides a unique insight into one's intellectual condition.