Hans Vaihinger

Hans Vaihinger (Nehren, 1852 – Halle, 1933) was a German philosopher working in the Kantian tradition. He is best known as a scholar of Kant and for his book The Philosophy of 'As If' (1911). His lasting interest lies in having put the role of fictions in science and everyday life at the center of philosophy well before it became a common topic.

Born near Tübingen in Württemberg, he grew up in what he later described as a very religious atmosphere. He studied at Tübingen, Leipzig and Berlin, then worked as a tutor before becoming a philosophy professor at Strasbourg. In 1884 he moved to the University of Halle, where he became a full professor in 1892. Around 1900 his health declined, above all his eyesight, and he had to give up his chair. In 1926 he became completely blind.

In The Philosophy of 'As If' he argues that human beings can never truly know the underlying reality of the world. We therefore build systems of thought and behave as if they match what is real. He illustrates this with physics: protons, electrons and electromagnetic waves have never been observed directly, yet science treats them as existing and uses the results to build better models. He separates half-fictions, which depart only slightly from the facts, from real fictions, which contradict themselves, such as the concept of the atom or Kant's 'thing in itself'. The idea reaches beyond science. We can never be sure the world will still exist tomorrow, yet we act as though it will.

His influence was uneven. Alfred Adler, founder of Individual Psychology, drew on his theory of fictions, and later George Kelly and James Hillman developed related ideas. Frank Kermode cited him as a useful guide to narrative. After the Second World War his work was largely neglected by philosophers, but today the fictionalist movement in the philosophy of science treats him as a key forerunner.