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. Descartes started writing the work in 1628, and it was eventually published in 1701 after Descartes' death. This treatise outlined the basis for his later work on complex problems of mathematics, geometry, science, and philosophy. 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.
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| II || We must occupy ourselves only with those objects that our intellectual powers appear competent to know certainly and indubitably.
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| IV || There is a need for of a method for finding out the truth.
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| XIV || The problem should be re-expressed in terms of the real extension of bodies and should be pictured in our imagination entirely by means of bare figures. Thus it will be perceived much more distinctly by our intellect.