Regulae ad directionem ingenii, or Rules for the Direction of the Mind is an unfinished treatise regarding the proper method for scientific and philosophical thinking by René Descartes.
[1] This treatise outlined the basis for his later work on complex problems of mathematics, geometry, science, and philosophy.
[2] The work is estimated to have been written over approximately 10 years, and as such Descartes shifted in his utilization and definition of these rules.
Rules for the Direction of the Mind is described as a precursor and 'scrapbook' for his other workings and methods.
Rules 1-12 deal with the definition of science, the principal operations of the scientific method (intuition, deduction, and enumeration), and what Descartes terms "simple propositions", which "occur to us spontaneously" and which are objects of certain and evident cognition or intuition.