Template:Are You Sure/October 4

• ... that theoretical physicist Max Planck (23 April 1858 – 4 October 1947) lost much of his will to live after his son Erwin was arrested by and died at the hands of the Gestapo?

... that mathematician and actuary Harald Cramér became interested in the field of probability before it was accepted branch of mathematics, and in a 1926 paper in 1926 Cramér wrote: "The probability concept should be introduced by a purely mathematical definition, from which its fundamental properties and the classical theorems are deduced by purely mathematical operations."?