A science of exceptions, a science of imaginary solutions. Two notions were behind Pataphysics: that of equivalences and the clinamen or slight decline of atoms falling. In 1893, Jarry attributes to Pere Ubu the invention of Pataphysics, 'a science that we have invented and which is generally felt to be needed'. But the real founding text is another: the Gestes et opinions du docteur Faustroll, pataphysicien, a work finished in 1898 and published in 1911, four years after Jarry's death. Book II, titled Elements de pataphysique only occupied two pages but is of primary importance because it contains the first definition of it,, which has never failed to be given as a reference: 'Pataphysics is the science that added to metaphysics, either in itself or outside itself , and extend as far beyond metaphysics as the latter extends beyond physics. Pataphysics is the science of imaginary solutions that symbolically attributes to the feature the properties of the objects described according to their virtuality'. The doctrine cannot actually be explained. Let us add that this science is also presented as the science of the particular and it deals with the rules governed by exceptions. Naturally the rule is 'an exception to the exception'. In other words, everything is pataphysics. The pataphysical dialectic revolves around itself like the ubic (spiral-shaped) navel that is its emblem. Extract from Alfred Jarry- De los Navis a la Patafísica, Catálogo producción IVAM Institut d'Art Modern, Valencia, 2000. Chapter: From painting to pataphysics, by Emmanuel Gujón.