Janina Hosiasson-Lindenbaum

Works

• 1940On Confirmation

  In the Journal of Symbolic Logic: a probabilistic account of confirmation that explains why a black raven confirms “all ravens are black” more than a white shoe does.

Position

Hosiasson-Lindenbaum belongs to the probabilistic line of the Lwów–Warsaw School. She treated induction not as a method of discovery but as a logic of degrees of belief: inductive inferences are justified to the extent that they can be described in the calculus of probability. In “On Confirmation” (1940) she gave axioms for a degree of confirmation and applied them to the paradox Carl Gustav Hempel had formulated: if “all ravens are black” is equivalent to “all non-black things are non-ravens”, a white shoe seems to confirm a hypothesis about ravens. Her answer – that, given far fewer ravens than non-black things, a black raven raises the probability of the hypothesis much more than a white shoe – became the core of the standard Bayesian reply. Hempel discussed it in 1945 and Rudolf Carnap took up her axioms in his “Logical Foundations of Probability” (1950). Later authors such as I. J. Good (1967) showed that the result depends on background assumptions, and that under some of them a black raven can even disconfirm the hypothesis. Her murder ended the work early; she was long known mainly through footnotes and has been rediscovered by recent research on the history of confirmation theory and on women in early analytic philosophy.

Life & context

Janina Hosiasson was born in 1899 in Warsaw into a Jewish family. She studied philosophy at the University of Warsaw, where Tadeusz Kotarbiński and Jan Łukasiewicz were among her teachers, and earned her doctorate there. She married the logician Adolf Lindenbaum, a collaborator of Alfred Tarski. She never held a university chair and earned her living mainly as a teacher, while publishing in Polish, English and French: on why we prefer probabilities relative to many data (“Mind”, 1931), on whether probability theory is a generalised logic (1936), on confirmation (“Journal of Symbolic Logic”, 1940) and on induction and analogy (“Mind”, 1941). She took part in the international congresses of scientific philosophy in the 1930s and was in contact with members of the Vienna Circle. After the German invasion of Poland in 1939 she and Lindenbaum fled to Vilnius, then under Lithuanian and from 1940 Soviet rule. Lindenbaum was murdered in 1941. After the German occupation of the city Hosiasson-Lindenbaum was arrested and murdered by the Germans, probably in 1942 at Ponary (Paneriai) near Vilnius; the exact date is not documented.

Further main works

• Why Do We Prefer Probabilities Relative to Many Data? (Mind, 1931)
• Is the Theory of Probability a Generalised Logic? (La théorie des probabilités est-elle une logique généralisée?, 1936)
• Induction and Analogy (Induction et analogie: comparaison de leur fondement, Mind, 1941)

Appears in

• Journey ‘Philosophy under National Socialism’ · Stop 8 of 10