Person of the week : George Boole (1815 – 1864)

Boole

 

George Boole, the son of a cobbler, was born in Lincoln, England, in November 1815. Because of his family’s difficult financial situation, Boole had to struggle to educate himself while supporting his family. Nevertheless, he became one of the most important mathematicians of the 1800s. Although he considered a career as a clergyman, he decided instead to go into teaching and soon afterward opened a school of his own. In his preparation for teaching mathematics, Boole – unsatisfied with textbooks of his day – decided to read the works of great the great mathematicians. While reading papers of the great French mathematician Lagrange, Boole made discoveries in the calculus of variations, the branch of analysis dealing with finding curves and surfaces optimizing certain parameters.

In 1848 Boole published The Mathematical Analysis of Logic, the first of his contributions to symbolic logic. In 1849 he was appointed professor of mathematics at Queen’s College in Cork, Ireland. In 1854 he published The Laws of Thought, his most famous work. In this book, Boole introduced what is now called Boolean algebra in his honor. Boole wrote textbooks on differential equations and on difference equations that were used in Great Britain until the end of the nineteenth century. Boole married in 1855; his wife was niece of the professor of Greek at Queen’s College. In 1864 Boole died from pneumonia, which he contracted as a result of keeping a lecture engagement even though he was soaking wet from a rainstorm.

Person of the week : Alan Mathison Turing (23 June 1912 – 7 June 1954)

Alan_Turing_photo

Alan Turing, was a British mathematician, logician, crypt-analyst, philosopher, computer scientist and mathematical biologist. He provided a formalization of the concepts of “algorithm” and “computation” with the Turing machine, which can be considered a model of a general purpose computer. Turing is also considered to be the father of theoretical computer science and artificial intelligence.

During World War II, Turing worked for the Government Code and Cypher School (GC&CS) at Bletchley Park, Britain’s code-breaking center. Turing’s pivotal role in cracking intercepted coded messages enabled the Allies to defeat the Nazis in several crucial battles. After the war, he worked at the National Physical Laboratory, where he designed the ACE, among the first designs for a stored-program computer.

He was born in London but conceived in India, where his father was employed in the Indian Civil Services. As a boy, he was fascinated by chemistry, performing a wide variety of experiments, and by machinery. Turing attended Sherborne, an English boarding school. In 1931, he won a scholarship to King’s College, Cambridge. After completing his dissertation, which included a rediscovery of the Central Limit Theorem, a famous Theorem in statistics, he was elected a fellow of his college.

In 1935, Turing became fascinated with a decision problem, a problem by the great German mathematician Hilbert, which asked whether there is a general method that can be applied to any assertion to determine whether the assertion is true. Turing enjoyed running and one day, while resting after a run, he discovered the key ideas needed to solve the decision problem. In his solution, he invented what is now called a Turing machine as the most general model of a computing machine. Using these machines, he found a problem, involving what he called computable numbers, that could not be decided using a general method.

From 1936 to 1938 Turing visited Princeton University to work with Alonzo Church, who had also solved Hilbert’s decision problem. In 1939 Turing returned  to King’s College. However, at the outbreak of World War II, he joined the Foreign Office, performing cryptanalysis of German ciphers. His contribution to the breaking of the code of the Enigma, a mechanical German cipher machine, played an important role in winning the war.

After the war, Turing worked on the development of early computers. He was interested in the ability of machines to think, proposing that if a computer could not be distinguished from a person based on written replies to questions, it should be considered to be “thinking.” He was also interested in biology, having written on morphogenesis, the development of form in organisms. In 1954 Turing committed suicide by taking cyanide, without leaving a clear explanation.

Person of the week : ARISTOTLE (384 BC – 322 BC)

Aristotle

Aristotle was born in Stagirus (Stagira) in northern Greece. His father was personal physician of the King of Macedonia. Because his father died when Aristotle was young, Aristotle could not follow the custom of following his father’s profession. Aristotle became an orphan at a young age when his mother also died. His guardian, who raised him, taught him poetry, rhetoric, and Greek. At the age of 17, his guardian sent him to Athens to further his education. Aristotle joined Plato’s Academy where for 20 years he attended Plato’s lectures, later presenting his own lectures on rhetoric. When Plato died in 347 BC, Aristotle was not chosen to succeed him because his views differed too much from those of Plato. Instead, Aristotle joined the court of King Hermeas where he remained for three years, and married the niece of the King. When the Persians defeated Hermeas, Aristotle moved to Mytilene and, at the invitation of King Philip of Macedonia, he tutored Alexander, Philip’s son, who later became Alexander the Great. Aristotle tutored Alexander for five years and after the death of King Philip, he returned to Athens and set up his own school, called Lyceum.

Aristotle’s followers were called the peripatetics, which means “to walk about”, because Aristotle often walked around as he discussed philosophical questions. Aristotle taught at Lyceum for thirteen years where he lectured to his advanced students in morning and gave popular lectures to a broad audience in the evening. When Alexander the Great died in 323 BC, a backlash against anything related to Alexander led to trumped-up charges of impiety against Aristotle. Aristotle fled to Chalcis to avoid prosecution. He only lived one year in Chalcis and died in Euboea in 322 BC.

Aristotle wrote three types of works: those written for a popular audience, compilations of scientific facts, and systematic treatises. The systematic treatises included works on logic, philosophy, psychology, physics, and natural history. Aristotle’s writings were preserved by a student and were hidden in a vault where a wealthy book collector discovered then about 200 years later. They were taken to Rome, where they were studied by scholars and issued in new editions, preserving them for posterity.

According to the Encyclopædia Britannica, “Aristotle was the first genuine scientist in history … [and] every scientist is in his debt.”