1901 – Born on the 16th of November in Czech Republic,Prague.
1923 – He gained a BSc degree from the City College of New York.
1930 – Earned his PhD from Columbia University.
1931 – He earned his PhD from Columbia University.
1966 – He spent his entire academic career at Columbia.
1967 – He become a University Professor.
1958 – He wrote An Introduction to Logic and the Scientific Method.
1985 – Died on the 22nd of September in New York City.