Rules for the Direction of the Mind

In 1628 or a few years earlier, René Descartes began work on an unfinished treatise regarding the proper method for scientific and philosophical thinking entitled Regulae ad directionem ingenii, or Rules for the Direction of the Mind. This work outlined the basis for his later work on complex problems of mathematics, science, and philosophy. 36 rules were planned in total, although only 21 were actually written. This work was not published during the author's lifetime. A Dutch translation appeared in 1684, and the first Latin edition in 1701.

The first 12 rules deal with his proposed scientific methodology in general. Analysts consider them to be early versions of principles that he expanded upon in his later writings.