writings of men capable of giving good instructions. Higher wisdom There have been great men in all times that have sought after a better and more secure wisdom, a fifth degree of knowledge. This has consisted on the search for the first causes, and those that have followed this pursuit have been named philosophers, but he thinks that no one has been successful yet. Doubt and certainty Since Plato and Aristotle, there has been a discussion about doubt and certainty. Those that have favored doubt have arrived to extremes of doubting even the most evident things, and those that have sought certainty have relied excessively on the senses. Though it is true that it has been accepted that the senses may mislead us, according to Descartes, nobody had yet expressed that the truth can not be based on the senses, but in the understanding, when it is founded on evident perceptions. Meditations on first philosophy The search for the first causes, or basic truths, as undertaken by Descartes is contained in this work. It explains the metaphysical principles on which to build the rest of knowledge. The tree of philosophy The philosophy is like a tree, whose roots are the metaphysics, its trunk the physics, and the branches the rest of sciences, mainly medicine, mechanics, and morals that is the last level of wisdom. In the same way that the tree has its fruits in its outer parts, the usefulness of philosophy is also contained in the parts that are learnt at the end. Copies and modern editions A copy of Descartes' Principia philosophiae dated 1656 is owned by the Tom Slick rare book collection at the Southwest Research Institute in Texas. Reidel, a Dutch publisher, released an English edition of Principia philosophiae in 1983 (), translated by Valentine Rodger and Reese P. Miller with explanatory notes. Though a translation of the original 1644 Latin work, this edition by Rodger and Miller includes additional material from the 1647 French translation. See also Bucket argument Conservation of momentum Related works The World (Descartes) Principia philosophiae cartesianae by Baruch Spinoza References External links Descartes' 1644 Principia philosophiae (free Google eBook) Selections from the Principles of Philosophy at Project Gutenberg Principles of Philosophy, modified for easier reading Principia philosophiae. Amstelodami, apud Ludovicum Elzevirium, 1644. From the Rare Book and Special Collections Division at the Library of Congress 1644 books Physics books Works by