The world of experience, the Phenomenal, consists of element less relations that defy definitions. Our phenomenal picture of the world thus emerges as a complex of ´relations as such´. In criticizing the logician´s naive hope of building a purely logical representation of the world, Josephine Pasternak proposes a categorical approach to cognition that avoids the pitfalls of classical and modern logic. Like her brother Boris Pasternak, Josephine Pasternak draws up a philosophical and poetic vision of the world. »It is a real philosophical thought« Dame Iris Murdoch writes in her preface, and continues »deep and stirring, and presented with authority and elegance. I am so glad that it will be published.« Josephine Pasternak was born in Moscow in 1900. In 1921 she moved to Germany, where she studied Philosophy at the Universities in Berlin and Munich. In 1929 she was awarded a Dr. phil. for a thesis on the psychology of perception, in 1938 she moved to England, and took up residence in Oxford, where she lived for the rest of her life, until her death in 1993. She has previously published Ein Beitrag zur Lehre von den akustischen Intermittenzerscheinungen; two books of poems in Russian, and the memoirs of her father, the Russian portrait painter, Leonid Pasternak. Indefinability is edited by Arne Frimuth Petersen, Professor of Psychology at the Faculty of Humanities, University of Copenhagen, with assistance of Helen Ramsay, Josephine Pasternak´s daughter. Preface by Dame Iris Murdoch, Oxford. Introduction by Michael Slater, Reader in Mathematics, University of Bristol.