Principles of Philosophy (Barnes & Noble Library of Essential Reading)

by Rene Descartes, John Veitch (Translator), Paul Hoyt-OConnor (Introduction)

Overview

René Descartes is perhaps most remembered for declaring, “I think; therefore, I am.”  First published in 1644, Descartes’s Principles of Philosophy elucidates the meaning of those words that ushered in a new era of philosophical thought.  Unlike the medieval philosophers who often began by examining the existence and nature of God in a spirit of faith, Descartes begins by reflecting upon himself as one who doubts but who nonetheless desires certain knowledge of God and the world.  In setting forth the truths he discovers, Descartes hoped that his Principles of Philosophy would provide a new basis for human knowledge and, most especially, a new footing for scientific inquiry.

Product Details

ISBN-13:	9781411429376
Publisher:	Barnes & Noble
Publication date:	09/01/2009
Series:	Barnes & Noble Library of Essential Reading
Sold by:	Barnes & Noble
Format:	eBook
Pages:	112
File size:	526 KB
Age Range:	3 Months to 18 Years

About the Author

René Descartes (1596–1650) is hailed as one of the greatest thinkers of the modern age and considered the Founder of Modern Philosophy, and the Father of Modern Mathematics.   Descartes abandoned his early study of law and devoted his life to investigating the relationship between mathematics and nature.  His founding of analytical geometry paved the way for the invention of calculus and the Scientific Revolution.

Read an Excerpt

From the Introduction by Paul Hoyt-OConner 

Renowned mathematician, scientist, and philosopher, René Descartes is perhaps most remembered for declaring, “I think; therefore, I am.”  First published in 1644, Descartes’ Principles of Philosophy elucidates the meaning of those words, which ushered in a new era of philosophical thought.  Unlike the medieval philosophers before him, who often began by examining the existence and nature of God in a spirit of faith, Descartes begins by reflecting upon himself as one who doubts but who nonetheless desires certain knowledge of God and the world.  In setting forth the truths he discovers and other key elements of his philosophical system, Descartes hoped that his Principles of Philosophy would provide a new basis for human knowledge and, especially, a new footing for scientific inquiry. 

René Descartes was born on March 31, 1596, in Touraine, France.  His mother died the following year, and his father, who served as a magistrate, left the family estate for months at a time when the local parliament was in session.  As a result, the young Descartes was sent in 1606 to the highly regarded Jesuit college at La Flèche, where he studied logic, mathematics, and philosophy.  Receiving a degree in law in 1614, he left behind the study of books in order to study “the book of the world”; and in 1618, as the conflicts comprising the Thirty Years War broke out across the European continent, he entered the army of Prince Maurice of Nassau and, later, that of Maximilian I of Bavaria.  After leaving the military in 1628, Descartes settled in Holland, which was then a noted haven for religious nonconformists.  It was there that he penned most of his philosophical works, including: Discourse on Method, which together with essays on optics, meteors, and geometry was published in French in 1637; Meditations on First Philosophy, published in Latin in 1641; Principles of Philosophy, published in Latin in 1644; and The Passions of the Soul, published in French in 1649.  At the invitation of Queen Christina, Descartes left Holland in the fall of 1649 for Sweden.  Unaccustomed to the long Swedish winters and the demanding schedule of the queen, Descartes contracted a fever and died on February 11, 1650.

Descartes’ Discourse on Method is largely an autobiographical account of the development of the method he employs in his scientific and philosophical investigations.  Similarly, Meditations on First Philosophy is a personal narrative that invites its readers to reflect upon their conscious acts as Descartes seeks to uncover those certain truths that are so central to his own philosophizing. Descartes circulated copies of his Meditations prior to publication in the hope of collecting objections to his thought from some of the leading thinkers of the day, and a volume of those objections and his replies accompanied the work on publication. Much to the consternation of Descartes, Meditations did indeed stir considerable controversy.

That is why the style of Principles of Philosophy differs so significantly from his earlier writings; he was pressed to alter his approach, in part, by the many questions his earlier works had raised.  In Principles, Descartes systematically argues the fundamental elements of his philosophical and scientific thought, the presentation of his ideas having clearly benefited from his replies to those earlier objections. The result is that Principles contains more precise formulations and helpful clarifications of some of the central tenets of Descartes’ philosophical thought. 

Though their styles differ, the general contour of Descartes’ thought in his earlier works and in Principles remains consistent.  As Descartes himself suggests in his letter that introduces the first French edition of Principles published in 1647, Meditations might serve as the best preface to the ideas contained in the work.  In both texts, Descartes begins by regarding as false whatever in the least may be doubted.  His exaggerated or “hyperbolic” doubt extends not only to what may be presented to us by our senses, for what we now sense may be only a figment of our dreams.  His doubt extends also to our mathematical and logical thought, perhaps surprising for someone such as Descartes, who, from an early age admired the certainty attainable in mathematics. 

For Descartes, we all have discovered ourselves to be in error though we felt absolutely certain in our claims, and it is at least possible to suppose that our maker is an “evil genie,” a devilish being who fashions our nature in such a way that we are always prone to error no matter how certain we feel.  Descartes thus marshals the challenges to both sources of knowledge that are reminiscent of the “academics,” those ancient skeptics who were the heirs to Plato’s Academy and whose arguments had of late gained some currency in France through Michel de Montaigne’s Essays, published in the later part of the previous century. 

We may perhaps regard as false whatever we sense, imagine, feel, and think.  Descartes, however, cannot doubt that he who thus doubts must in fact exist.  Thus, “cogito, ergo sum,” “I think; therefore, I am,” becomes for Descartes the “first principle” of his philosophy and the cornerstone of his thought.  The “I” that exists, though, is quite distinct from the bodily “I” perceived before one; indeed, the presentations of the senses are still subject to his exaggerated doubt.  As a “thinking thing,” a “res cogitans,” the “I” not only thinks, but also feels, senses, desires, perceives, understands, conceives, and wills, with those conscious activities comprising so many “modes” of a “substance” that exists in itself.  Descartes’ affirmation of the existence of himself as a thinking subject that is distinct from his own body and, consequently, his identification of two distinct substances of mind and matter and their corresponding “attributes”—indeed it is in the Principles that he gives sharper definition to such terms as “substance,” “mode,” and “attribute”—shape the thought of a number of philosophers who came after him, most especially Benedict de Spinoza and Gottfried Wilhelm Leibniz.  For that reason among others, Descartes is often regarded as the founder of modern philosophy.

Nonetheless, there are numerous ways in which Descartes’ thought is reminiscent of earlier, medieval thinkers.  For example, in the Fourth Set of Objections to Descartes’ Meditations, Antoine Arnauld, a prominent theologian associated with the Jansenists of Port-Royal and a friend of Blaise Pascal, noted some historical antecedents of Descartes’ first principle.  That the claim “I exist” resists the arguments of the skeptics was a truth recognized earlier by Augustine of Hippo who wrote, “Si enim fallor, sum,” or “If I am mistaken, I am.”[i]  While there is a striking similarity between their formulations, the place that each truth occupies in its respective philosophy differs greatly.  In contrast to Augustine, Descartes made this truth the first principle in the orderly progression of his thought. 

Others questioned whether that truth could at all be affirmed as “first” without knowing other, more fundamental truths.  For instance, the philosophers and theologians who submitted the Sixth Set of Objections to Descartes’ Meditations questioned whether the affirmation “I think; therefore, I am” already supposes that one knows the meanings of such terms as “thought” and “existence.”  The very formulation of this principle, furthermore, suggests that Descartes’ apprehension of his own existence appears to be a conclusion derived from more fundamental, though unstated, premises.  After all, Descartes does use the word “ergo,” “therefore.” 

Descartes contends, however, that the apprehension of the truth of his existence is not a reasoned conclusion but a self-evident perception.  Indeed, all such truths that withstand the exercise of his exaggerated doubt must be just as certain and self-evident.  Thus he holds that those ideas which he “clearly and distinctly perceives” are ones he can affirm as true, and we fall prey to error if, held captive by our prejudices, we make judgments though such evidence is lacking.  It is in the Principles that Descartes formulates more precisely what he means by such terms as “clarity” and “distinctness” that are central to his understanding of truth.

His existence is but one of the truths that Descartes claims is certain.  Another is the existence of God, and in Principles, he recasts the three arguments that one may find in his Meditations and Discourse.  The order of these arguments differs, though.  Descartes’ ontological argument, the best known of the three, comes first rather than last in Principles, perhaps indicating that he believes that it is logically prior to the others.  Any ontological argument for the existence of God is one that argues that existence belongs necessarily to the very idea of God.  In his argument, Descartes holds that just as he clearly and distinctly perceives that the sum of a triangle’s angles equals 180° belongs necessarily to the idea of a triangle, so he clearly and distinctly perceives that existence is a perfection that belongs necessarily to God as a “supremely perfect being.”  His other arguments in Principles—namely, that as an imperfect being he cannot be the cause of the idea of God as an infinitely perfect being, and that as a being who possesses such an idea of God he cannot be the cause of his own existence—benefit from distinctions that have been refined through responding to earlier objections to these arguments initially set forth in his Meditations.

As a supremely perfect and existent being, God is also morally perfect by Descartes’ account.  Establishing God’s veracity or truthfulness is crucial if he is to dispel the shadow of the evil genie he conjured while casting doubts upon the validity of his past and present thinking.  For Descartes, God’s moral perfection is pivotal for assuring that we are not deceived in holding “what nature teaches us”: that not only does the external, material world exist, but so also does my very body as a part of that world.  The substance of an extended thing, or “res extensa,” differs essentially from the mind that thinks and knows itself to exist, though, and corporeal beings are those that natural science investigates.  That we can be certain that God is not deceiving us is crucial for Descartes in establishing the certainty of the scientific knowledge we may acquire of our bodies and of the material universe, and he devotes parts 2–4 of Principles to elaborating the foundations for such science.  As he does so, Descartes is pressed to consider more thoroughly the nature of the unity of the mind and body, even though they are two really distinct substances on his own account.  Descartes addressed this issue in part at the urging of Princess Elizabeth of Bohemia, a student and patron to whom he dedicated Principles, which provides a lengthier discussion of the relation between the mind and body than is found in his earlier works. 

More fundamentally, though, Descartes seeks to chart a new course for natural philosophy and a mathematical physics.  In setting out to establish new foundations for natural science, he self-consciously parts ways with the Aristotelian natural philosophy in which he was originally schooled.  For Aristotle and his medieval followers, often referred to as “the scholastics” or “the schoolmen,” one comes to know natural things by coming to know their “causes,” including their formal, material, efficient, and final causes.  In contrast, Descartes sought to give accounts of material things quite apart from any appeals to their formal causes or their immaterial “quiddities” or “essences,” since the scholastic debates regarding them seemed to him to be interminable and unproductive.  He also wished to give accounts that did not appeal to final causes, or purposes or “ends” of things, since that knowledge would seem to entail reading the mind of the infinite God, an impossible task for finite beings such as we are.  Instead of seeking to understand the essences and the purposes of things, natural philosophy by Descartes’ account seeks to grasp the material and efficient causes of things, attending especially to their number, figure, and motion.  In so doing, he sought to grasp the necessary and certain laws governing matter in motion, laws that, as Galileo Galilei (1564–1642) had earlier hoped, might be mathematically formulated. 

Descartes was all too aware of the controversies surrounding that work which eventually led to Galileo’s arrest by religious authorities, and Descartes himself remained quite circumspect so that he would not likewise become embroiled in similar disputes.  In large measure, the case against Galileo turned on whether he held that the heliocentric conception of the solar system was simply a useful hypothesis or was instead a statement of fact that would be at odds with scriptural depictions of the heavens.  For that reason, Descartes was careful to point out that the account he wished to give was indeed hypothetical though powerfully explanatory. In keeping with the depiction of the “tree of philosophy” drawn in his introductory letter to the first French edition, he hoped that the physics he envisioned in Principles would bear considerable fruit in the various branches of human knowledge, most notably in medicine and ethics.

Descartes’ view that true science is beneficial and knowledge powerful is one shared with English philosopher and statesman Sir Francis Bacon (1561–1626).  Though Descartes was the more accomplished scientist and mathematician, Bacon perhaps saw more clearly the role experimentation would play in the emerging natural, empirical sciences.  In place of Aristotelian natural science of the past, both Descartes and Bacon sought to promote and advance a more “productive” knowledge of nature.  Descartes wrote his Principles of Philosophy in the hopes of providing the foundation of a science that promised to yield unprecedented benefits for humankind.

Paul Hoyt-O’Connor received his Ph.D. in philosophy from Boston College.  He is the Lilly Fellow in the Center of Religion, Ethics, and Culture at College of the Holy Cross in Worcester, Massachusetts.

Endnote

[i]  See, for instance, Augustine, City of God, book 11, 26, and On Free Choice of the Will, book 2, 8.