# Cartesian

In general, this refers to something that can be linked back to Rene Descartes, the French scientist, famous for uttering the phrase, “I think, therefore I am.”

There are several scientific, mathematical, and philosophical branches that are named for Descartes:

- Cartesian geometry
- Cartesian philosophy
- Cartesian doubt
- Cartesian dualism
- Cartesian coordinates
- Cartesian tree

In fact, there is an entire philosophic and scientific systems called Cartesianism.

## Why I Looked It Up

I was reading something that mentioned “Cartesian” and “Descartes” in the same sentence, and I suddenly connected the two. I had mainly known the phrase “Cartesian coordinates.”

## Postscript

Added on

From *The Deepest Map*:

Decartes created the way to change the visual world into a world of numbers, and vice-versa, that is now called Cartesian geometry. Draw two perpendicular axes on a page, and any point placed on the page can be identified by two numbers.

## Postscript

Added on

In *Broadway: A History of New York City in Thirteen Miles*:

The 1811 Commissioner’s Plan was a product of the American Enlightenment, Cartesian in its insistence on straight lines.

I looked up Cartesian Geometry, and found this:

Usually the Cartesian coordinate system is applied to manipulate equations for planes, straight lines, and circles, often in two and sometimes three dimensions. Geometrically, one studies the Euclidean plane (two dimensions) and Euclidean space. As taught in school books, analytic geometry can be explained more simply: it is concerned with defining and representing geometric shapes in a numerical way and extracting numerical information from shapes’ numerical definitions and representations.

That doesn’t make a whole lot of sense to me, but it does tie it into Euclidiean geometry. I don’t know which is which, really.