“Logic is the foundation of the certainty of all the knowledge we acquire”

There are very few people in history who have done true justice to the meaning of the word ‘Polymath’. Hailing from the quaint town of Basel, Switzerland, Leonhard Euler is undoubtedly the greatest mathematician of all time.

Apart from being a superior mathematician, he was also a physicist, a logician, an engineer, a geographer, and an astronomer. He made ground-breaking contributions to many branches of mathematics such as Analytic Number Theory, Analysis, Topology, Infinitesimal Calculus, Graph Theory etc.

At a young age, his family moved to the town of Riehen, where he spent most of his childhood. He was extremely fortunate to have been mentored by Johann Bernoulli himself, who proved to be a lasting influence on him. Bernoulli’s recognition of the prodigy inside young Leonhard made him convince his father to allow him to continue his mathematical studies.

His textbooks on calculus, Institutiones calculi differentialis, and Institutiones calculi integralis served as a foundation for textbooks of the later generations as it had many mathematical concepts that are useful in solving physical problems. He also had an unusual knack for pedagogy, as is evident in his Letters to a German, On different subjects in Physics and Philosophy, where he was asked to tutor German Princess Friederike Charlotte of Brandenburg-Schwedt and her younger sister, Louise Wilhelmine. Incurring the envy of Frederick II, due to his immense contributions, he was forced to leave Berlin, but he soon accepted the patronage of Catherine II and settled in Russia.

His major accomplishments in astronomy include determining the path of celestial bodies with great accuracy, calculating the parallax of the Sun, understanding the nature of comets, etc. He devoted a significant amount of time trying to devise a more accurate theory for the motion of the Moon which led to the evolution of the 3-body problem, which still stands unsolved to date.

In the course of his mathematical career, Euler’s eyesight started worsening. He had lost his right eye in 1738 for which he blamed the laborious cartography work assigned at the St. Petersburg Academy. In 1766, a cataract and a botched surgery left him totally blind. But, in an anime-esque sort of twist, his productivity only increased, reaching to a stage where he produced one mathematical paper every week in 1775 with the aid of scribes. What he lost in terms of vision, he compensated for, with his eidetic memory and mental mathematics.

In 1783, when he was discussing the then newly discovered planet, Uranus and its orbit with fellow academic Anders Johan Laxell, he collapsed due to a cerebral hemorrhage and breathed his last, a few hours later. In his eulogy, French philosopher Marquis de Condorcet wrote: *il cessa de calculer et de Vivre* (He ceased to calculate and to live). This marked the end of a once-in-a-millennium phenomenon that was Euler.

“*Read Euler, read Euler, for he is the master of us all*”

– Pierre-Simon Laplace

*Samarth Prabhu*

*Second Year ME*