U četvrtak 23.10.2014. u 19.00 sati

prof.dr.sc. **Zvonimir Šikić**

s Fakulteta strojarstva i brodogradnje Sveučilišta u Zagrebu će održati predavanje pod naslovom

**Što je vjerojatnost i zašto je važna**.

Predavanje se održava u sklopu redovitog Znanstvenog kolokvija SMD-a. Pozivamo sve zainteresirane da dođu na ovo predavanje u navedenom terminu u predavaonicu 22 PMF-a u Splitu, Teslina 12.

WHAT IS PROBABILITY AND WHY DOES IT MATTER

ZVONIMIR ŠIKIĆ University of Zagreb

ABSTRACT: The idea that probability is a degree of rational belief seemed too vague for a foundation of a mathematical theory. It was certainly not obvious that degrees of rational belief had to be governed by the probability axioms as used by Laplace and other prestatistical probabilityst. The axioms seemed arbitrary in their interpretation. To eliminate the arbitrariness, the statisticians of the early 20th century drastically restricted the possible applications of the probability theory, by insisting that probabilities had to be interpreted as relative frequencies, which obviously satisfied the probability axioms, and so the arbitrariness was removed. But the frequentist approach turned more subjective thaen the prestatistical approach, because the identifications of outcome spaces, the choices of test statistics, the declarations of what rejection regions are, the choices of null-hypothesis among alternatives, the contradictory choices between sizes and powers etc., depend on thoughts or even whims of the experimenter. Frequentists thus failed to solve the problems that motivated their approach, they even exacerbated them. The subjective Bbayesianism of Ramsey and de Finetti did not solve the problems either. Finally Cox provided the missing foundation for probability as a degree of rational belief, which makes the bayesianBayesian probability theory (which is based on this foundation) the best theory of probable inference we have. We explain the history and prove Cox theorem in a novel way. Keywords : probability, subjective Bayesianism, logical Bayesianism, Cox theorem To appear in „European Journal Of Analytic Philosophy“