Girolamo Cardano (1501-1576) was the son of a lawyer in Milan, whose expertise in mathematics was such that he was consulted by Leonardo da Vinci on questions of geometry. Cardano studied medicine, and was a brilliant student but outspoken and highly critical of his fellow professionionals. He was awarded his doctorate in medicine in 1525. He set up a small, and not very successful, medical practice in Sacco, where he married. He was a keen gambler and turned to it to make a living. He repeatedly applied to the College of Physicians in Milan but was not allowed membership due to his reputation. Unable to practise medicine he continued to gamble heavily. He obtained the post of lecturer in mathematics in Milan, and despite not being a member of the College of Physicians began treating patients. His growing reputation as a doctor led to his being consulted by members of the College, to which he was eventually admitted in 1539.
In the same year, Cardano’s first 2 mathematical books were published. This was the beginning of Cardano’s prolific literary career writing on a diversity of topics medicine, philosophy, astronomy and theology, in addition to mathematics. For many years, Cardano worked on solving cubic and quartic equations by radicals and did some of the first calculations with complex numbers. In 1545 Cardano published his greatest mathematical work Ars Magna. In it he gave the methods of solution of the cubic and quartic equation.
He became rector of the College of Physicians and gained the reputation of being the greatest physician in the world. Cardano received many offers from the heads of state in Europe, anxious to receive the best medical attention. Cardano was appointed professor of medicine at Pavia University.
Around this time, Cardano’s eldest son secretly married a girl whom he later poisoned. Following his arrest, he confessed to the crime and he was executed. In 1570, Cardano himself was put in jail on the charge of heresy for casting the horoscope of Jesus Christ. On his release a few months later, he was forbidden to hold a university post and barred from further publication of his work.
In addition to Cardano’s major contributions to algebra he also made important contributions to probability, hydrodynamics, mechanics and geology. Cardano made the first foray into the untouched realm of probability theory. Cardano also published 2 encyclopaedias of natural science, which contain a little of everything, from cosmology to the construction of machines, from the usefulness of natural sciences to the evil influence of demons, from the laws of mechanics to cryptology.
Cardano is reported to have correctly predicted the exact date of his own death but it has been claimed that he achieved this by committing suicide.
Cardano’s understanding of probability meant he had an advantage over his opponents and, in general, he won more than he lost. Gambling became an addiction that was to last many years and rob Cardano of valuable time, money and reputation.
De Vita Propria Liber – The Book of My Life by Girolamo Cardano