Gerolamo Cardano Italian mathematician, engineer, philosopher, physician and astrologer, inventor of the cardan shaft Date of Birth: 24.09.1501 Country: Italy

1. Biography of Gerolamo Cardano
2. Education and Medical Career
3. Interests and Contributions
4. Later Life and Tragic Events

Biography of Gerolamo Cardano

Gerolamo Cardano was an Italian mathematician, engineer, philosopher, physician, and astrologer, who is best known for inventing the Cardan shaft. He was born in Pavia, Italy, on September 24, 1501. He was the son of Fazio Cardano, a renowned lawyer who was mentioned by Leonardo da Vinci.

Education and Medical Career

In 1526, Gerolamo Cardano graduated from the University of Padua and attempted to become a practicing physician in a nearby town. However, being an illegitimate child posed difficulties for his acceptance into the College of Physicians. Cardano returned to Milan and began giving lectures on mathematics. He then practiced medicine in the province for a long time, and in 1539, he was finally accepted into the College, with the rules for admission being specifically changed for him. Soon, Cardano became the rector of the College and a renowned physician. He detailed his medical research in his autobiography, claiming to have developed methods to treat 5,000 incurable diseases, resolved 40,000 serious medical issues, and addressed 200,000 minor ones. While these numbers should not be taken too seriously, Cardano's reputation as a physician was undeniable, as he was invited to treat notable individuals such as the Scottish Archbishop Hamilton and Cardinal Maron.

Interests and Contributions

In his free time, Cardano engaged in a wide range of activities, including composing horoscopes for the living and the dead (even providing astrological services to the Pope), interpreting dreams, and creating various fantastic theories. Alongside these pursuits, he also had serious scientific interests. His book "On the Subtle Matters" (De Subtilitate Rerum) served as a popular textbook on statics and hydrostatics throughout the 17th century. Galileo followed Cardano's suggestion on the use of one's pulse rate for measuring time. Cardano's musings on the creation of a perpetual motion machine and the distinction between electrical and magnetic attraction were also noteworthy.

Cardano conducted experimental research and designed various mechanisms, with the most well-known being the Cardan shaft. He was also an avid gambler, and his love for dice games prompted him to write the book "On Games of Chance" (De Ludo Alea, 1563), which laid the foundations of probability theory, formulated the law of large numbers, and explored combinatorial questions. His renowned work on mathematics, "The Great Art" (Ars Magna, 1545), became a cornerstone of modern algebra. In this work, Cardano attempted to systematize the study of equations, conducted operations with imaginary numbers, and, for the first time, published a method for solving cubic and quartic equations (the solution for the quartic equation was discovered by Cardano's student, Luigi Ferrari). The publication of Ars Magna led to a famous dispute between Cardano and Niccolò Tartaglia, a lecturer from Venice, regarding priority in solving these equations. The method for solving cubic equations had already been discovered by Scipione del Ferro from Bologna in 1515. In 1535, Tartaglia independently invented his own method and shared it with Cardano, taking an oath from the latter to keep the discovery a secret. Nevertheless, Cardano published everything he knew about cubic equations in his book, stating that he was aware of Ferro's earlier work, which freed him from any obligations to Tartaglia. Tartaglia accused Cardano of treachery in his book, published in 1546. The dispute ended after a public debate in 1548, in which Ferrari represented Cardano's interests. Only brief records of the debate remain, but it seems that Tartaglia suffered a devastating defeat.

Later Life and Tragic Events

The last years of Cardano's life were marked by tragic events. His son, also a physician in Milan, was executed in 1560 for poisoning his unfaithful wife. In 1562, Cardano was appointed as a professor in Bologna, but in 1570, he was arrested by the Inquisition. The exact charges against him are unknown, but he was sentenced relatively leniently, with the prohibition to publish his works. He spent the rest of his life in Rome, trying to seek forgiveness. Gerolamo Cardano passed away in Rome on September 20, 1576.