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# Euclid

## The Father of Geometry

### TL;DR

Euclid of Alexandria authored “The Elements,” a foundational textbook in mathematics that systematized ancient knowledge. His work emphasized clear definitions, axioms, and logical proofs, setting the standard for over two millennia. Some argue that besides the Bible, no other book in the Western world matches “The Elements” in terms of success and influence.

Euclid of Alexandria played a pivotal role in organizing and consolidating the knowledge of mathematics from ancient Greek and Near Eastern cultures. He penned “The Elements,” which stands as the most influential textbook on mathematics ever written.

We have scarce information about Euclid’s personal life. Proclus of Athens, a Greek philosopher from around 410-485 CE, provides our primary insights, even though he lived seven centuries after Euclid. Based on Proclus’s accounts, Euclid taught in Alexandria, Egypt, during the reign of Ptolemy I Soter from 323 to 285 BCE. Apart from this, details about Euclid’s birthplace, birth year, or the year he passed away remain a mystery. He apparently authored roughly a dozen books, but most of them have been lost with time.

Euclid by Jusepe de Ribera, c. 1630–1635

Proclus shared a tale about Euclid wherein Ptolemy inquired if there was a simpler method to understand geometry. Euclid’s famous reply was, “There is no royal road to geometry.”

Within “The Elements,” Euclid didn’t merely present known techniques. He dove deep into the rationale behind them. Before Euclid’s time, ancient Egyptians used geometry based on empirical findings. For instance, to estimate a circle’s area, they would draw a square whose sides measured eight-ninths of the circle’s diameter. Their technique suggests that the value of pi was 3.16, which is a slight deviation from the actual value of approximately 3.14. Such approximations were satisfactory for their engineering tasks.

Euclid’s primary genius in “The Elements” lay in four main areas. First, he consolidated essential mathematical knowledge into one comprehensive text. Though The Elements serves as a textbook and not an exhaustive reference, it encompasses a wide range of topics.

Second, Euclid laid out clear definitions, postulates, and axioms, referring to axioms as “common notions.”

Third, he structured geometry as an axiomatic system. Every claim in the book was either an axiom, postulate, or derived logically from them.

Lastly, among his contributions were some unique discoveries, notably the pioneering proof that prime numbers are infinite.

Despite many of the concepts not being entirely original, the true essence of “The Elements” is its systematic, coherent assembly of ideas backed by mathematical proofs. Even now, these principles remain fundamental for geometry students. Euclid’s approach to geometry was once regarded as the definitive system. Thus, to distinguish it from geometries discovered in the 19th century, we term it “Euclidean geometry.”

**What has been affirmed without proof can also be denied without proof.**

Given the diverse complexity of Euclid’s book, some believe he might have compiled works from various mathematicians. While parts of this belief might hold water, distinguishing between Euclid’s original work and adaptations remains a challenge. His peers viewed “The Elements” as definitive, meaning any additional contributions would have to be a commentary on his work.

“The Elements” first saw print in 1482, and its logical structure led to over a thousand reprints in the years that followed. By the early 1900s, most schools had phased out “The Elements” as a textbook, but some persisted with it into the 1980s. However, its theories remain integral to modern geometry.

Interestingly, there has been some confusion in history, as medieval editors and translators mistakenly associated Euclid with philosopher Eukleides of Megara, who lived around a hundred years before Euclid’s time. This resulted in the mistaken moniker, Megarensis.

Title page of Sir Henry Billingsley’s first English version of Euclid’s Elements, 1570. Billingsley erroneously attributed the original work to Euclid of Megara.

From its inception, “The Elements” profoundly impacted human civilization. It served as the cornerstone for geometric theories, proofs, and methodologies until the emergence of non-Euclidean geometry in the 19th century. Some argue that besides the Bible, no other book in the Western world matches “The Elements” in terms of success and influence. While some might not place Euclid among the most elite mathematicians, his emphasis on deductive logic and geometric instruction established a gold standard that endured for over two millennia.

### Words of wisdom

“Yesterday is gone. Tomorrow has not yet come. We have only today. Let us begin.” ―Mother Teresa

“Have no fear of perfection―you’ll never reach it.” ―Salvador Dali

“A year from now you may wish you had started today.” ―Karen Lamb

“I learned that courage was not the absence of fear, but the triumph over it. The brave man is not he who does not feel afraid, but he who conquers that fear.” ―Nelson Mandela

### Bibliography

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