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|First Name=ReneRené

|SummaryBrief='''Rene Descartes''' (1596-1650) was a French mathematician and natural philosopher. ; who is today considered one of the most influential figures in modern philosophy|Summary=Descartes rejected the Aristotelian-scholastic world view medieval mosaic accepted for most of the previous two thousand years, and laid down new the foundations for knowledge. He is widely regarded as the founder of modern philosophya new mechanistic mosaic.[[CiteRef::Russell (1945)|p. 524]][[CiteRef::Newman (2014)]][[CiteRef::Garber (1993)]] Descartes put forward his new approach Aristotelians had maintained that intuition schooled by experience was the route to knowledge . Descartes, in his ''Discourse on the Method of Rightly Conducting One’s Reason and of Seeking Truth in the Sciences'' (''Discourse on Method''), first published in 1637.,[[CiteRef::Descartes (2007)]] Descartes posited put forward a rationalist scientific methodology whereby in which a proposition is acceptable only if it can be clearly and distinctly perceived by the intellect beyond all reasonable doubt or follows deductively from such propositions.[[CiteRef::Newman (2014)]] This allowed him to advance a mathematical a priorist approach to scientific knowledge and inquiry.[[CiteRef::Garber (1992)]][[CiteRef::Clarke (1992)]] Rejecting the Aristotelian world of forms, substances, and teleology, he posited a mechanical world in which matter possessed only spatial extension and interacted only by contact. This allowed him to advance In mathematics he developed techniques that made possible analytic geometry. In natural philosophy, he was co-framer of the sine law of light refraction, developed a mathematical theory of the rainbow, and formulated a priorist approach to scientific knowledge and inquiryprecursor of the nebular hypothesis of the origin of the solar system.[[CiteRef::Garber (1992)]][[CiteRef::Clarke Hatfield (19922016)]]|Historical Context=The [[Scientific Mosaic|scientific mosaic ]] of the late sixteenth and early seventeenth centuries was based primarily on the works of [[Aristotle ]] and some later Hellenistic natural philosophers, . This was reconciled in various ways with Christian theology by scholars in the High Middle Ages. This '''Aristotelian-scholastic mosaic ''' included Christian theologyPtolemaic astronomy, astrology, humoral physiology, astrology, Ptolemaic astronomy, and Christian (Catholic, in many but not all communities contemporaneous with Descartes) theology.[[CiteRef::Haldane (1905)]] Descartes was well educated in this tradition through his attendance at the prestigious Jesuit La Fleche College between the ages of ten and eighteen. He studied a traditional scholastic curriculum of logic, grammar, philosophy, mathematics, and theology under Jesuit instruction. Natural philosophy was taught from the works of Aristotleas interpreted by Christian scholars. He is known to have Descartes also received an education in mathematics that was unusual for the Aristotelian tradition, and excelled at math.[[CiteRef::Gaukroger (1995)|pp. 38-61]][[CiteRef::Rodis-Lewis (1992)]][[CiteRef::Garber (1992)]]

Descartes’ major writings came in a time of social and intellectual upheaval in Europe. He Before writing his major works, he was a participant in the Thirty Years War before writing his major works and traveled . He travelled extensively around Europe at a time when the continent was embroiled in both reformation and counter-reformation, both of which were both a wellspring of new thought in theology and philosophy. The community of the time was engaged with major challenges to the Aristotelian-scholastic tradition. These came from varied sources, including varieties of Platonism, Hermeticism, and the chemical philosophy of Paracelsus, among other movements.[[CiteRef::Garber (1992)]] There were major new developments in optics, astronomy, and physiology.[[CiteRef::Cottingham (1992)]] The community of the time was engaged with major challenges to the Aristotelian-scholastic tradition. Aristotle's earth-centered cosmology had been challenged by the work of Nicolaus Copernicus(1473-1543), Johannes Kepler(1571-1630), and GalileoGalilei(1564-1642), which Descartes was familiar with.[[CiteRef::Hatfield (2016)]][[CiteRef::Rodis-Lewis (1992)]] Although he was critical of Galileo’s methodology it is clear that he nevertheless had read and was familiar with his work, which was instrumental in weakening the various communities’ confidence in the Aristotelian mosaic.[[CiteRef::Ariew (1986)]]

Corpuscularism After leaving La Fleche, in 1618,Descartes became involved in a collaboration with the Dutch Calvinist natural philosopher Isaac Beeckman (1588-1687), who valued him for his mathematical skills. They worked together on several mathematical problems in natural philosophy. [[CiteRef::Gaukroger (1995)|p. 68]] Beeckman was a supporter of the '''mechanical natural philosophy'''. This was a [[Theory Pursuit|pursued ]] radical alternative to Aristotelian cosmology, embraced by some supporters of Copernican heliocentrism.[[CiteRef::Luthy, Murdoch, and Newman (2001b)]][[CiteRef::Chalmers (2014)]][[CiteRef::Gaukroger (1995)|p. 69-73]] It rejected the Aristotelian fundamentals of form, substance, and teleology, and the idea that matter is continuous. Instead of explaining the properties of visible bodies in terms of form, it maintained that the world consisted of invisibly tiny particles of matter and that all the observable properties of the natural world visible bodies were a consequence of these particles and their interactions with one another. The particles interacted were held to interact mechanically, by contact, and it was often supposed that they this rendered natural phenomena potentially explainable in geometrical and mathematical terms. Corpuscularism derived from It can be traced to the Ancient Greek '''atomism ''' of Democritus (circa 460-370 BCE) and later Epicurean philosophers. Atomism was reintroduced into European thought in the fifteenth century with the rediscovery of the Roman poet Lucretius's ''De rerum natura''. Part of its appeal lay in the fact that unlike Aristotle's physics, the mechanical philosophy was compatible with a moving planetary Earth. In the decades before Descartesearly seventeenth century, it was championed by Giordano Bruno (1548-1600), Nicolas Hill (1570-1610?), Sebastian Basso (1573-1625?), Francis Bacon (1561-1626), whose empiricist epistemology challenged Aristotelian-scholastic methods,and Galileo Galilei.[[CiteRef::Garber (1992)]][[CiteRef::Klein (2012)]] and in the speculative cosmology of Giordano Bruno (1548-1600).[[CiteRef::Gatti (2001)]][[CiteRef::Luthy, Murdoch, and Newman (2001b)]]

After leaving La Fleche, Descartes became involved and Beeckman worked together on several mathematical problems in a collaboration with the Dutch Calvinist natural philosopher Isaac philosophy. Beeckman, who valued him for his mathematical skillsis almost certainly the first person in Europe to attempt to explain macro-geometrical regularities in terms of micro-mechanical models.[[CiteRef::Gaukroger (1995)|p. 6870]] Beeckman led For the most part, applying mathematics to physical problems was not part of the Aristotelian tradition. Descartesadopted Beeckman' adoption of s mathematical corpuscularism and introduction to became part of a community of corpuscularist thinkers which besides Beeckman and Descartes included Marin Mersenne (1588-1648), Thomas Hobbes (1588-1679), Pierre Gassendi (1592-1655), Sir Kenelm Digby (1603-1665), and Walter Charleston (1620-1707). They all knew each other and reacted to each other's work.[[CiteRef::Osler (2001)]] Their work directly conflicted with The decade after Descartes met Beeckman was the Aristotelian tradition by positing atomism and by rejecting plenismmost philosophically productive of his life.[[CiteRef::Rodis-Lewis Garber (1992)]] These and other factors place Descartes in a historical context rife with revolutionary change and immense scholarly interest in the changing landscape of academic inquiry.

In terms of his methodology Descartes was largely responding to what he perceived as the dogmatism and marked lack of progress he perceived saw in the Scholastic tradition within which he was schooled at La Fleche. His motivations for undertaking , and his investigations in the way he did are well documented in his writings and correspondences. He was unsatisfied excitement with the education he received in college and frustrated with the conservatism of his instructorsnew mechanical natural philosophy. In part one of the Discourse on the Method he writes “there is nothing at stake for the scholar except perhaps that the further his conclusions are from common sense the prouder he will be of them because he will have had to use so much more skill and ingenuity in trying to make them plausible!”[[CiteRef::Descartes (2007)]] His weariness with the largely dialectical scholastic method is what led him to develop the highly systematized epistemology and metaphysics for which he would come to be known. The Aristotelian-scholastic mosaic continued to be [[Theory Acceptance|accepted]] throughout Descartes's life, with acceptance of his views coming later.|Major Contributions=Descartes was instrumental new methodology and mechanical natural philosophy were of revolutionary importance. They became accepted at Cambridge University in England by 1680,[[CiteRef::Barseghyan (2015)|p. 211]] and in revolutionizing France by about 1700, displacing the Aristotelian-medieval system of theories that had been central elements of the [[Scientific Mosaic|scientific mosaic of seventeenth-century ]] for centuries. These theories were ultimately fully displaced throughout Europe by proposing a new methodology, new core scientific Descartes' theories in physics and mathematics, and new understandings by the later theories of epistemology and metaphysics[[Isaac Newton]] (1642-1726).[[CiteRef::Barseghyan (2015)|p.167]]

===Cartesian MethodMethodology===Under the Aristotelian scholastic [[Methodology|methodology]] a theory is acceptable “if it grasps the nature of a thing through intuition schooled by experience, or if it is deduced from general intuitive principles”.[[CiteRef::Barseghyan (2015)|p. 144]] Descartes became frustrated with this tradition and its dialectical approach to knowledge-seeking, which he charged with plunging him into skeptical doubts whereby he could never be sure what was true and what was not. He writes in ''Discourse on Method'':[[CiteRef::Descartes (2007)]]

The most notable <blockquote>“But no sooner had I completed the whole course of Descartes’ contributions was his introduction of a new method for pursuing knowledge in the science study that was distinct from normally takes one straight into the previously accepted method inherited from Aristotle. Descartes had become frustrated with the previous method ranks of the Scholastic European tradition and its dialectical approach to knowledge-seeking, which he charged with plunging him into skeptical doubts whereby he ‘learned’ than I completely changed my mind about what this education could never be sure what was true and what was notdo for me. He writes For I found myself tangled in Discourse on the Method:so many doubts and errors that I came to think that my attempts to become educated had done me no good except to give me a steadily widening view of my ignorance!”</blockquote>

“But no sooner had I completed the whole course of study that normally takes one straight into the ranks of the ‘learned’ than I completely changed my mind about what this education could do for me. For I found myself tangled in so many doubts and errors that I came to think that my attempts to become educated had done me no good except to give me a steadily widening view of my ignorance!”[[CiteRef::Descartes (2007)]]Descartes concluded that if his goal was to attain certain knowledge about the world then ,the presently accepted method was insufficient methodology for doing so must be rejected, and that a new one would be required to satisfy his aimsformulated. Method was a central theme in Descartes’ writing and Methodology held a central place in Descartes’ his epistemology; in fact, one of Descartes’ criticisms of Galileo was that he failed to produce a fully developed method methodology to justify his discoveries, and had simply explained particular physical phenomena.[[CiteRef::Ariew (1986)]] To that end he embraced his sceptical doubts Rather than experience and devised a method intuition, Descartes' '''methodological skepticism''' was based on methodological scepticism; a method whereby he rejects all knowledge that he cannot be certain of, accepts only those propositions which he can accept as certain, reason and proceed deductively from those axioms according on the capacity to reasondoubt. By this method Descartes hoped to produce The harder a kind of systematized knowledge that could be universally acceptable. As it happened the sole indubitable proposition upon which he would build the entire rest of his philosophical system was his famous ‘Cogitoto doubt, Ergo Sum’ (also styled ‘Dubito, Ergo Cogito, Ergo Sum’ or simply as ‘the Cogito’); “I think, therefore I amthe greater its certainty.” From this foundation Descartes deduced his being a created thing, his requiring a creator, that creator being God, the nature of God, and the reliability of his senses and reason, all of which would form the broader foundation of his systematized scientific worldviewThis was an epistemological innovation.[[CiteRef::Newman (2014)]]

Although Descartes maintained some methodological aspects His strategy was, first, to reject all knowledge that he cannot be certain of the Scholastic-Aristotelian mosaic – namely the axiomatic-deductive, epistemic-foundationalist structure and accept only those propositions of investigation – one critical difference in Descartes’ methodology was the shift in the which he is certain. He would deduce other knowledge from such axioms using reason. By this method of theory choice. According Descartes hoped to Barseghyan, the accepted method produce a kind of the Scholastic-Aristotelian method was systematized knowledge that a theory is acceptable “if it grasps the nature of a thing through intuition schooled by experiencecould be universally accepted. In his ''Meditations on First Philosophy'', or if it is deduced from general intuitive principles.”[[CiteRef::Barseghyan Descartes (20152004)]] The keywords Descartes identified the sole indubitable proposition upon which he would build his entire philosophical system: he was certain of his own existence as a thinking being, or in this formulation Latin, '''''‘Cogito, Ergo Sum’''''' (also styled ''‘Dubito, Ergo Cogito, Ergo Sum’'' or simply as ''‘the Cogito’''); “I think, therefore I am.” From the foundation of the Scholastic-Aristotelian method are intuition and experiencehis own existence, both of which are necessary conditions for one to Descartes deduced that he must be justified in accepting a proposition. Descartes’ methodology is notable in created being, that this requires a creator, that it jettisons both creator being God, the benevolent nature of those conditions; a proposition need be neither experientially based nor intuited for it to be acceptableGod, and although the consequent reliability of his senses and of the God-given ability of his system as it ended up allowed for knowledge that reason to form clear and distinct ideas. It was both experiential therefore possible to use his senses and intuited,reason to gain knowledge of an external world. This reasoning formed the foundation of his systematized scientific worldview.[[CiteRef::Newman (2014)]] the ultimate justification for knowledge claims was human reason. In this way Descartes is both a rationalist and an apriorist, in that his epistemology and metaphysics allows for the existence of synthetic a priori propositions.

===The Cartesian Revolution Descartes maintained some aspects of the Scholastic-Aristotelian methodology – namely an axiomatic-deductive, epistemic-foundationalist structure of investigation. But the critical difference in Natural Philosophy===his methodology was the shift in the method of theory choice. He jettisoned the Aristotelian expectation that a theory must be experientially based and intuitively obvious for it to be acceptable, and although his system, as it ended up, allowed for knowledge that was both experiential and intuited,[[CiteRef::Newman (2014)]] the ultimate justification for knowledge claims was human reason and the absence of doubt. Descartes was both a '''rationalist''' and an '''a priorist''', in that his epistemology and metaphysics allows for the existence of synthetic a priori propositions. Although an argument for God's existence was at the foundation of his system, Descartes' rationalism was nonetheless a formidable challenge to the accepted theological methodology which had been comprehensively expressed by the Catholic saint, Thomas Aquinas (1225-1274) more than three hundred years earlier. Aquinas saw human reason as limited, and always to be exercised in the context of, and subject to the authority of, the divine revelation of the Bible. Descartes, by contrast, sought to develop his epistemology and theology on the basis of human reason alone. [[CiteRef:: Hyman (2007)]]

{{#evt:service=youtube==Cartesian Natural Philosophy===Descartes scientific theories about the natural world were grounded in a metaphysical foundation, in turn deduced by the application of his rationalist methodology. He wrote that "the whole of philosophy is like a tree. The roots are metaphysics, the trunk is physics, and the branches emerging from the trunk are all the other sciences, which may be reduced to three principle ones, namely medicine, mechanics, and morals".[[CiteRef::Clarke (1992)|id=yFH7i3Lx7IAp. 271]] One ought to construct a metaphysics first, based on criteria independent of observation, and subsequently consider physical theories consistent with the metaphysical foundation. His natural philosophy was in stark contrast to the accepted Aristotelianism. In Aristotelian natural philosophy all objects were a compound of form and matter, a concept called hylomorphism. Form gives material bodies their distinctive properties, and makes them different from one another. It explains why fire rises and stones fall. Matter is what all material bodies share in common. All things have teleological goals or purposes. [[CiteRef::Shields (2016)]] |alignment=right|description=Hakob BarseghyanIn Descartes' mechanical corpuscular natural philosophy, by contrast, there are just two kinds of substance that are entirely different from each other in kind: mental substance and physical substance. The fundamental property of '''mental substance''' was thought, and Descartes equated it with the rational soul of God and humans. The fundamental feature of '''physical substance''' was extension in space. He rejected Aristotle's distinction between form and matter, including Aristotle's lecture four elements. [[CiteRef::Ariew (1992)]] Cartesian mechanics rejects the void posited by atomists; instead matter fills the universe as a plenum. If all matter is extended, Descartes reasoned that there can be no space without extended matter. Also unlike atomism, matter is infinitely divisible, though visible things are composed of tiny corpuscles that interact with one another by physical contact. The corpuscular composition of a material body, rather than its Aristotelian form, determines its properties. Since corpuscles are too small to be directly observed, their size and shape must be hypothesized, though observation can allow us to infer the plausibility of our guesswork. Our senses, Descartes maintained, do not inform us of the mechanical world as it is, but provide us with sensations which are mere signs of their objective causes. Only extended matter and motion exist apart from our minds. [[CiteRef::Clarke (1992)]] Descartes completed a manuscript that was to be a comprehensive expression of his mechanical natural philosophy, called ''The World''. He withdrew his plans to publish it upon learning of the condemnation of Galileo in Rome in 1633. The work never appeared during his lifetime, but two major fragments, the ''Treatise on Light'', and the ''Treatise on Cartesian WorldviewMan'' were published posthumously. The first dealt with physics, and the second put forward a theory of physiology, nervous system function, and the mind/brain relationship. [[CiteRef::Garber (1992)]][[CiteRef::Descartes (2003)]]|container=frame }}In Descartes cosmology, the universe is essentially mechanical in character. Copernican heliocentrism is accepted, and planetary motion is explained in terms of a swirling '''vortex''' of material particles around the central sun. Earth, as a moving planet, is the center of its own smaller vortex. The particles of the vortex push larger bodies towards its center and this explains gravity without supposing, as did Aristotle, that the sphere of earth was at rest in its natural place; the center of the universe. It also made it reasonable to suppose that other planets had their own attractive vorticies, and were thus other worlds. [[CiteRef::Garber (1992)]]

Descartes played a pivotal role in also challenged Aristotelian physiology. Aristotle's theory of physiology posited three souls or vital principles; the nutritive soul, responsible for nutrition and reproduction, comprised the transition away from entirety of the Scholastic-Aristotelian mosaicsoul in plants. The sensitive soul, and his physicalresponsible for perception, physiologicallocomotion, psychologicalimagination, and biological theories are too numerous desire, was added to be adequately treated herethe sensitive soul in animals. A third component, the intellectual soul, was found uniquely in human beings.[[CiteRef::Hatfield Shields (20162016b)]][[CiteRef::Garber Van der Eijk (19922000)]] That said, a number of his theories are worth exploring in brief, in particular those that were fundamental departures from the accepted mosaic of the early sixteenth century. The first and most dramatic of these is Descartes’ rejection of hylomorphism and the form-matter distinction which would be the foundation for Descartes’ rejection of most of the prior physics. In place of the hylomorphic theory of substance Descartes proposed that there are in fact two kinds of substances that are entirely different from each other in composition and kind: mental substance and physical substance. Descartes equated the former with rejected the rational soul of God nutritive and humans and the latter with all physical mattersensitive souls, supposing their functions were instead performed by corpuscular mechanisms, the fundamental feature nature of which he considered to be extensionoutlined in his ''Treatise on Man''. [[CiteRef::Descartes deduced his scientific theories about the natural world from this basically metaphysical foundation (all of which he deduces by application of his method2007). For example ]] Descartes' mental substance served roughly the central concept in Cartesian mechanics is that all material interactions are interactions between matter, which fills the universe (plenism also followed from Descartes’ position of matter same role as extension because if all matter is extended then there can be no space without extended matterAristotle's intellectual soul. Animals, i.e. a vacuum). Descartes also considered the universe to be essentially mechanical in character except for mental substance – animals according to Descartes, as being constituted solely are complex automata composed of material physical substance and without mental substance, are mere automata only and cannot be said to think, feel, or love in the way that human beings or God can; these properties being made possible by mental substance.[[CiteRef::Des Chene (2001)]][[CiteRef::Clarke (1992)]][[CiteRef::Descartes (2007)]] Descartes posited a mental substance for theological, metaphysical, and scientific reasons. He supposed that thought could not be mechanized, since all the machines known to him were specialized to perform one particular function, but human reason was a general purpose instrument.[[CiteRef::Hatfield (1992)]][[CiteRef::Cottingham (1992)]]

The details of the Cartesian school of Descartes mechanical natural philosophy are not as important however as the impact that the school would have on subsequent scientific inquiryfostered a radical change in how natural philosophers gained new knowledge. The overthrow of the Aristotelian tradition, even -medieval methodology accorded a very limited role for experiments in places where Cartesianism scientific investigation. This is because a strict distinction was rejected made between natural and the community maintained Aristotelianismartificial things. Every natural thing behaved in accordance with its nature; acorns grow on oak trees, forced the academic community in Europe to reconsider because that is what their nature dictates. Artificial things have an external source of change. The cogs and defend the Aristotelian mosaic in ways springs of a clock are constructed so that had never before been encountered. Though the dialectical approach they no longer behave according to their respective natures (which is simply to scholarship throughout fall towards their natural place at the medieval period saw scholars constantly questioning various aspects center of the Aristotelian worldview Descartes’ wholesale rejection universe, rather than function as parts of huge swaths a machine that tells time for humans). A thing cannot reveal its true nature under the artificial conditions of experimentation, because the mosaic and its central concepts were unprecedentedexperimental set up necessarily puts things under artificial conditions. Theories like hylomorphismTo gain knowledge, which had been a given things must be observed in their natural undisturbed state. Descartes' mechanical natural philosophy rejected the mosaic natural/artificial distinction along with its rejection of forms and teleology. Matter always obeyed the sixteenth and early seventeenth centuries and had endured through multitudes same set of mechanical laws regardless of its situation. Thus,under the mechanical natural philosophy experimentation was often a good source of adjustmentsknowledge about nature, reconciliations and dialectic criticism had never before faced complete overhaul as Descartes threatened. Although Descartes would eventually be supplanted by Newton he made the critical first steps to replacing the Scholastic-Aristotelian mosaicits adherents often became practitioners.[[CiteRef::Hatfield Barseghyan (20162015)|p.181-182]]|Criticism=Descartes’ ideas saw widespread criticism in his time and shortly after from all manner of sources, including Scholastic vanguards, religious authorities, and other philosophers. By 2016 almost all of Descartes’ ideas have been consigned to the graveyard of ideas, but it is worth noting some criticisms Descartes faced in his lifetime or shortly thereafter that are of historical interest.

The most notable objection Descartes would end up facing would be challenge to the more mathematically precise Aristotelian tradition, even in places where Cartesianism was rejected and more explanatorily powerful physical theory given by Newton half a century laterthe community maintained Aristotelianism, but there existed objection forced the academic community in Europe to Descartes even earlierreconsider and defend the Aristotelian mosaic in ways that had never before been encountered. One particularly notable objection came from Princess Elizabeth Though the dialectical approach to scholarship throughout the medieval period saw scholars constantly questioning various aspects of Bohemiathe Aristotelian worldview, who questioned Descartes’ theory wholesale rejection of substance huge swaths of the mosaic and its central concepts were unprecedented. Theories like hylomorphism (that being is a compound of matter and form), which had been a given in a letter dated the tenth mosaic of Maythe sixteenth and early seventeenth centuries, 1643and had endured through multitudes of adjustments, reconciliations, and dialectic criticism, but had never before faced complete overhaul that Descartes's mechanical natural philosophy threatened. In itAlthough Descartes' theories would eventually be supplanted by those of Newton, she asks “Given that he made the critical first steps to replacing the soul Aristotelian-scholastic mosaic.[[CiteRef::Hatfield (2016)]]|Criticism=Descartes’ ideas saw widespread criticism in his time and shortly after from all manner of a human being is only a thinking substancesources, including Scholastic vanguards, how can it affect the bodily spiritsreligious authorities, in order and other philosophers. One common early criticism was that his new views were threatening to bring about voluntary actions?”the Catholic and Christian faith.[[CiteRef::Descartes Jolley (20091992)]] Descartes would never gives a satisfactory answer over In 1663, his works were placed on the course Catholic Church's ''Index of the correspondenceForbidden books'', and in 1671 his conception was officially banned from schools in the single example highlights how troubling the issues left open by Descartes’ system are for Catholic world. In the integrity of that system. Elizabeth’s objection raises reasonable (significantearly modern period, even) doubts about whether or theological propositions and natural philosophical propositions were not the theory seen as belonging to separate domains, but rather formed parts of substance around which an integrated [[Scientific Mosaic|scientific mosaic]]. Aristotelian natural philosophy had been carefully adapted to render it consistent with Catholic faith. Descartes bases a significant portion of ' novel natural philosophy introduced many inconsistencies that needed to be [[The Zeroth Law|reconciled]] before his scientific theories can hold watercould be [[Theory Acceptance|accepted]]. [[CiteRef::Barseghyan (2015)|p. 190-196]]

One specific theological criticism of Cartesian natural philosophy had to do with the Catholic sacrament of the holy Eucharist, in which bread and wine are said to be transformed into the most powerful objections body and blood of Christ. The dogma of the ''Real Presence'' maintained that in this sacrament, Christ is really (as opposed to arise after Descartes’ death metaphorically or symbolically) present in 1650 came a generation later with the emergence bread and wine. Thomas Aquinas had posited an Aristotelian explanation for the ''Real Presence'' which had become the accepted Catholic ''doctrine of transubstantiation''. The doctrine held that in the Eucharist, the philosophy Aristotelian substance of John Locke the bread and wine were replaced by the British Empiricistsbody and blood of Christ, while their forms (that of bread and wine) remaining unchanged. LockeIn Descartes' corpuscularism, despite being an admirer bread and wine differed from flesh and blood because they had a different arrangement of Descartescorpuscles. There is no obvious way that one could appear as the other. The Anglican church, was highly critical the state church of England following its break with the Catholic papacy in the 1530's did not accept the ''doctrine of his methodology transubstantiation''. Thus Cartesianism did not face objections based on it, and became accepted at Cambridge University by 1680. Catholic Paris didn't accept it until 1700. Many solutions reconciling Cartesianism and the ''Real Presence'' had, by then, been proposed. Barseghyan speculates that the one accepted by the Parisian community was that proposed by Antoine Arnauld (1612-1694) in particular was critical of his methodological scepticism1671, in which Locke regarded as Christ's presence in the Eucharist was due to a non-startermiracle beyond human comprehension, and outside the ordinary course of nature described by Cartesianism.[[CiteRef::Uzgalis Barseghyan (20162015)|p. 194]]

Other objections Critics in Decartes' era were politicalalso concerned that corpuscular explanation involved hypothetical unobservable entities, theologicaland the supposition that this invisibly small world could be understood by analogy with larger objects. Descartes countered that "there is nothing more in keeping with reason that we judge about those things that we do not perceive, because of their small size, by comparison and personal objections brought by various interest groups contrast with those that we see" [[CiteRef::Clarke (1992)|p. 267]] He felt that a plausible model, though potentially incorrect due to the unobservability of its fundamental parts, was better than none at all. The role of unobservably small entities in the physical sciences was to remain a matter of prolonged debate. In modern science, it is an accepted and central practice. Another notable objection came from Princess Elizabeth of Bohemia (1618-1680), who had some stake questioned Descartes’ theory of substance in a letter dated the tenth of May, 1643. In it, she asks “Given that the soul of a human being is only a thinking substance, how can it affect the bodily spirits, in order to bring about voluntary actions?”[[CiteRef::Descartes (2009)]] Descartes would never gives a satisfactory answer to this central question over the course of the correspondence. In 1747, in his ''L'Homme machine''(''Machine Man'') Julien Offray de La Mettrie (1709-1751) raised another simple, but devastating objection to Descartes' supposition that human reason must be due to an immaterial mental substance. He noted that reason can become impaired by material causes such as drunkenness and fever. [[CiteRef::De La Mettrie (1996)]]. In the nineteenth century, Princess Elizabeth's objection became far more poignant with the formulation of the law of the conservation of energy, which implied causal closure of the academic status quophysical world to influence by a mental substance. In many places Descartes’ work the early twentieth century, the mathematician Alan Turing (1912-1954) showed that it was possible to construct a general purpose machine capable of performing any possible mathematical computation, thereby demonstrating that a general purpose machine was bannedpossible and refuting Descartes' core argument against a mechanical understanding of human reason. By the end of the twentieth century, the relevant scientific communities of neuroscience and cognitive science had rejected the idea of a mental substance and sought a mechanistic physical explanation for the mind [[CiteRef::Bechtel (2008)]], though there was still no agreement as to whether consciousness could be explained in this fashion. [[CiteRef::Chalmers (1996)]] Descartes' physical natural philosophy did not fare nearly so well. Within fifty years, Isaac Newton (1642-1726) formulated a more even discussion mathematically precise and explanatorily powerful physical theory, which became the accepted theory of the physical world. It rejected a major tenet of Descartes’ work Descartes' corpuscularism by positing a gravitational force that acted at a distance. Newton's laws of motion, however, bore important similarities to those formulated earlier by Descartes. [[CiteRef::Clarke (1992)]] As practicing scientists, researchers like Newton and Robert Boyle (1627-1691) did not, as did Descartes, seek certain knowledge of the real essences of material objects. Instead, they sought an ordering of phenomenal experience which would enable them to predict nature's course with the best available theory. [[CiteRef::Osler (1970)]] Descartes' method itself was bannedcriticized by two sympathetic figures; Antoine Arnauld and Marin Mersenne. Their criticism had to do with Descartes demonstration of the existence of God, which is the linchpin of his method. Official condemnations came down Descartes claimed that our belief in the reliability of the clear and distinct perceptions of the human intellect depends on our knowledge of the existence of God as the source of that capacity. But how could that knowledge be established in the first place? If we answer that we can prove God's existence from Universities premises we clearly and Church authoritiesdistinctly perceive, none then the argument collapses into circularity. Descartes' argument that it is possible for us to have certain scientific knowledge of which were effective at stopping the spread world fails with it, since it depends on God to underwrite the reliability of our senses and intellect. This criticism, called the '''Cartesian ideasCircle''', was never successfully countered. Within a generation, Descartes quest for certainty in scientific knowledge was widely recognized to have failed.[[CiteRef::Jolley Cottingham (1992)]] In 1650, [[John Locke]] and the British Empiricists brought forth a new conception of scientific knowledge that was more modest than Descartes' failed quest for certainty. The empiricists argued for experience, rather than a priori reason, as the basis for human knowledge, and sought a philosophy of science more in keeping with scientific practice. [[CiteRef::Uzgalis (2016)]][[CiteRef::Osler (1970)]]

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