Concerned about the understanding of his new interest for art brut, Jean Dubuffet used a culinary metaphor - with the intention to provoke. In his letter from 28 August 1945, destined to René Auberjonois, he extolls the merits of the milk straight from the buffalo, "fresh" and still keeping the warmth of the animal. Art brut is, according to him, like this potion. He compares it also to gold in its original state, golden nuggets which he "prefers to a watchcase". The concept of art brut is at that time brand new but it is significant to see it associated to the images which Dubuffet would often use later on. 
We can imagine that from the beginning this key word was, without any doubt, the consequence of a sensual process as well as an intellectual elaboration ; a natural atttitude in the case of a painter confronted with ideas as well as the matter. The invention of the word is sometimes attributed, however without any conclusive evidence, to Jean Paulhan, a (definitely more) cerebral writer.
Paulhan’s liking for secret nature that caused him to hide behind the false quotations of oriental sages as well as his intimate relationship with Dubuffet makes us favour such hypothesis. Be that as it may, it is of little importance. Great number of writers and artists, presented by Paulhan or those present at the dinners of Florence Gould, visited Dubuffet’s studio. There is no doubt that at that time the painter was immersed in fashionable and intellectual atmosphere, from which he would soon free himself ; it is, however, difficult to measure its influence. Even if many of his friends looked at Dubuffet’s passion for art brut with benevolence, no one identified as much as he did with this word. 
Art brut, until the donation of Dubuffet’s collection to Lausanne in 1976 and even until his death in 1985, would remain for Dubuffet who preferred this term to the more defensive one - art obscur, in translation obscure, humble art ("I would look as if pleading guilty") - a lantern and a tool, a conceptual arm and a source of worries, the core of his conception of the world of art.