Descartes Enigma is an implementation of a puzzle invented by Tetsuya Nishio.
Games Magazine publishes these types of puzzles periodically.  The more common
names for them are "Paint By Number," "Nonograms," and "Picross Puzzles."
In each of these puzzles, you are given a grid, which must be properly filled
in with white blocks and shaded blocks.  Each row and column has a series of
numbers associated with it that says how many groups of consecutive blocks
there are in it.

In the early stages of development, Descartes Enigma was referred to simply
as "PBN" (for "Paint By Number").  Everett Kaser began the project in
June 1998, and it wasn't until August 4th that its final name was finally
decided upon.  On June 26th, Everett used his new (at the time) site journal
section of his web page (http://www.kaser.com/journal.html) to start a contest
where readers could submit title suggestions.  Many of the names submitted
by readers were very good, particularly one I submitted ("Grasshoppers
Anonymous"), but none were used.  Everett thought of "Descartes Enigma" on
his own, and that's how the game got its name.  At one point, Everett mentioned
to me that this was the only game he'd had such trouble naming -- in the past,
the names had generally come to him without much effort.

A beta version of Descartes Enigma was released on the Everett Kaser Software
web site on August 31, 1998, and the completed game was released on
October 22, 1998.

Why that title?  Rene Descartes was a scientist and philosopher from the 17th
century who invented the now-named Cartesian coordinate system.  He co-invented
analytic geometry with Pierre de Fermat and coined the phrase, "Cogito, ergo
sum," which means, "I think, therefore I am."  Descartes' coordinate system
is integral to the puzzles in Descartes Enigma.

The clincher, so Everett says, that affirmed the title in his mind was a line
from the Encyclopedia Brittanica article about him: "At the end of his life,
he left a chest of personal papers -- none of which has survived -- with his
close friend, the Rosicrucian physician Corneille van Hogelande, who handled
his affairs in the Netherlands."  This "lost chest of Descartes" inspired
the back story of the game.