La géométrie by René Descartes

(4 User reviews)   2821
Descartes, René, 1596-1650 Descartes, René, 1596-1650
French
Ever wonder why we call those graph lines 'Cartesian coordinates'? This is the book that started it all. Forget dusty geometry class memories—Descartes' 'La Géométrie' is where math got a plot twist. He basically said, 'What if we could turn shapes into equations?' and then did it. It’s not a storybook, but the drama is real: it’s the moment algebra and geometry had a brilliant collision, changing science forever. Think of it as the original instruction manual for the grid paper that runs our world, from your phone's GPS to video game design. It's surprisingly readable for a 17th-century math manifesto.
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The second and third autographs have William written above Shakspere. Who but an illiterate person would sign his name thus? In the last two signatures (being told perhaps that his name ought to be written on one line) he puts William before Shakspere; but the fourth William reads Willin. See now how differently each letter is formed in the name Shakspere, beginning with the initial: Did anybody ever write the first letter of his name so differently? After four attempts to form a capital S he succeeds tolerably well the fifth time. The second S, though of singular shape, appears to have been a customary one as early as 1598. (See examples of that year below.) Shakspere’s first attempt to form the crooked letter is a failure, but the second passably good. So again in 1616, when he has a different form to copy, his first attempt is futile, the second is passable, and the third quite successful. But in attempting the next letter he makes it worse every time: With the letter a he is more successful, making it legible three times out of five: [5] But the attempt to form a k is a signal failure: With the long s he succeeds best the first time, and worst the second and third: The letter p is legible the first time, but grows worse and worse to the last: It seems as if in the first attempt to sign his name in 1613 he thought it was complete when he made it end with sp e; but being reminded that it lacked a letter or two he undertook to add one by putting an a over the e thus: The next time, which was probably the same day,(1) he seems to have written his name Shaksper, though the terminal letters are uncertain: The third time he gets it more like Shakspoze: The deed to Shakspere and two other trustees is dated March 10 and signed Henry Walker. The mortgage from Shakspere and the other trustees is dated March 11. But for some unaccountable reason a duplicate verbatim copy of the deed from Henry Walker is signed by William Shakspere. This duplicate is in the Library of the city of London; the mortgage is in the British Museum. The duplicate deed we suspect was signed after the mortgage. Hence the improvement in the autograph; it was probably Shakspere’s second attempt to write. Compare it with the third. [6] The fourth time he seems to have tried to disguise the termination with awkward flourishes, making the letters totally illegible: Finally, he omits the flourishes and comes nearer legibility, but still it is impossible to tell whether he meant to write _ear, ere, or eare_: And now let the reader mark, that notwithstanding the orthodox spelling of the name from 1593 to 1616, and indeed up to the present time, was and is Shakespeare, there is no e in the first syllable and no a in the last, although some have imagined the letter a to exist in the last part of the final autograph. We have said that these signatures are all that. Shakspere is known to have written; we ought to add that he prefixed to the last one the following scrawl: For a long time we puzzled over this. Could it be an attempt to write “25th of March,” the day of the execution of the will? At last we read the following in Hallowell-Phillipps’s Shakspere: “It may be observed that the words By me, which, the autograph excepted, are the only ones in the poet’s handwriting known to...

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Okay, let's be clear: this isn't a novel. There's no hero's journey, unless you count the journey of an idea. La Géométrie is the appendix to Descartes' bigger work, Discourse on the Method, but it's the part that blew up the math world. The 'plot' is simple: Descartes shows how you can use algebra—those equations with x's and y's—to solve problems about shapes and curves. Before this, geometry and algebra were like two separate languages. Descartes gave them a common dictionary: the coordinate plane. He drew two perpendicular lines, labeled them, and said any point could be described by a pair of numbers. Just like that, a circle wasn't just a drawing; it could be an equation (x² + y² = r²).

Why You Should Read It

Reading the original is like getting a backstage pass to a revolution. You see the moment of invention, complete with clunky 1600s notation. The genius is in the connection. It makes abstract math visual and visual problems solvable with logic. This book laid the groundwork for calculus, physics, and modern engineering. It’s humbling to see such a powerful tool explained from scratch, without any of the slick polish of a modern textbook.

Final Verdict

This is for the curious non-mathematician who loves 'aha!' moments in history. It's perfect for science fiction fans, tinkerers, or anyone who’s ever looked at a graph and wondered, 'Who thought of this?' You won't read it cover-to-cover like a thriller, but dipping into key sections is incredibly rewarding. It connects the dots between the abstract world of numbers and the physical world we live in. A foundational text that genuinely lives up to the hype.



📚 Legal Disclaimer

This text is dedicated to the public domain. It is now common property for all to enjoy.

Betty Sanchez
1 year ago

If you enjoy this genre, it creates a vivid world that you simply do not want to leave. This story will stay with me.

Ashley Wilson
1 year ago

Finally found time to read this!

Richard Miller
3 months ago

The index links actually work, which is rare!

William Anderson
8 months ago

Very helpful, thanks.

4.5
4.5 out of 5 (4 User reviews )

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