I. INTRODUCTION *

II. DESCARTES (1596-1550) *

III. DESCARTES’ METHOD *

IV. CARTESIAN DUALISM *

V. DESCARTES’ IMPACT ON MODERN PHILOSOPHY AND SCIENCE *

VI. OBJECTIONS TO DESCARTES *

VII. CONCLUSION *

I. INTRODUCTION
The purpose of this study is to examine Rene Descartes’ claims to knowledge, his epistemological method for grasping that which he considers to be knowledge, his assertion of the existence of a "God," and the impact of his thought upon modern philosophy and science.
Rene Descartes is considered the "Father of Modern Philosophy." His system of thought represents a break away from all former systems of philosophy, and particularly, away from Aristotle and Aquinas. Unlike Aristotle, who explained human existence in terms of "prime matter," and saw human beings as single unified entities, Descartes held that one has a mind and a body, each of which is a separate and distinct "substance." Unlike Aquinas, who argued for the tabula rasa model of the human mind—a mind that resembles a blank recording device at birth, and records data from sensory experience—Descartes argued that humans are born with innate ideas—ideas that exist in the mind at birth.

II. DESCARTES (1596-1550)
Descartes lived in an age that followed the renaissance—a time when people found a new appreciation for classical philosophy, art and literature. The renaissance was a revival of appreciation for the potential of the human mind, intelligence and human happiness here on this earth. The spirit of the age was in stark contrast to all of the previous centuries of church-dominated culture and thought which imagined human beings to be loathsome, wretched creatures tainted by "original sin," and whose proper function in life consisted of crawling on their knees in shame, self-disgust and humility. The Roman Catholic Church still had a great deal of political power over humankind during this age, although the "protestant reformation" of Luther, Calvin and their followers was in play. The "reformation" consisted of a schism or a breach in the once unified Church of Rome. Luther and Calvin accused the church of misleading the believers of Christianity, and made accusations of moral corruption within the church leadership. They encouraged people to reject the Catholic doctrines, and instead, to accept the new Protestant interpretations of scripture. Descartes, a Roman Catholic follower from cradle to grave, was concerned not only about the schism in the church, but the rise of skepticism—the denial that we can be certain of anything—and he sought to build a foundation for knowledge that could be held with all certainty, in opposition to the claims of the skeptics. Descartes maintained that we must challenge or suppress our premises, assumptions or underlying notions about everything. Because our senses sometimes deceive us, then perhaps we are wrong about everything that we imagine to be knowledge. And further, our reasoning as such may be wrong, evidenced by, for example, the multitude of religionists who imagine themselves to hold correct notions of a divine being, or god, each accusing the other of holding incorrect theological opinions, some of which are supposed to be punishable by damnation in hell. If we are deceived or in error about any one thing, then all of our notions may be wrong, and must be called into question if we hope to gain any knowledge whatsoever that can be held with absolute certainty.

III. DESCARTES’ METHOD
Descartes maintains that because our senses sometimes deceive us, then we must have no recourse to them if we are to discover knowledge that can be held with certainty. Instead, says Descartes, we must rely on human reason alone in our quest for genuine knowledge. This use of reason alone, without reference to human sense, is known today as "Rationalism," and Descartes is known as the "Father of Rationalism." In his Meditations, Descartes discounts the value of empirical knowledge, and he claims to have dispensed with all of his previously held notions, at least, for the purpose of his experiment in seeking reliable knowledge that can be held with certainty. He claims to have "detached his mind from his body," and he asks the reader to follow his reasoning as he begins his pursuit. Descartes claims that he is starting with a "clean slate" of mind with no knowledge whatsoever, and his goal is to discover whether anything can be grasped and discovered. In this way, Descartes sets himself up as a kind of moderator, or an impartial, disinterested and neutral judge with respect to the detection of truth. Here, the reader might have many objections and concerns about whether Descartes can fairly be said to be starting with a clean slate of mind resembling the tabula rasa model that Aquinas and other great philosophers have argued for, but we will address those concerns in a later section, and for the time being allow Descartes to present his case. It is worth noting that Descartes, a life long Roman Catholic, did not intend to actually discard his previously held opinions. On the contrary, he proposed to retain those opinions if they met the scrutiny of the principles that he made for his test of validity. Descartes’ four principles are as follows:
1. Accept nothing as true except clear and distinct ideas that cannot be doubted.
2. In order to arrive at reliable conclusions that can be held with certainty, divide each problem into many simpler parts, and test each part, rather than the problem as a whole.
3. Proceed in order from the simplest or easiest parts first, gradually working toward the complex without jumping to the complex.
4. Make complete and comprehensive surveys and checks to make sure that nothing has been overlooked or omitted.
According to Descartes, by following these principles, we can arrive at certainty in matters pertaining to metaphysics and philosophy, just as we can arrive at certainty in mathematics.
Descartes continues by suggesting that he cannot prove that he isn’t dreaming even though he believes that he is awake. And since dreams often contain phantasmical, chimerical and imaginary beings that are not to be found in what we think to be the reality of our waking lives, then we must not assume that the things that we experience in our waking lives are any more real than the things in our dreams unless and until our Cartesian experiment leads us to certainty as to which, if either, has reference to reality. And if all that we have just mentioned is not enough to induce doubt in the mind of the reader, then Descartes urges us to consider another prospect: perhaps some evil demon is tricking us into forming incorrect opinions and even into a false belief that we exist. In his Meditations, Descartes declares that "I will suppose that, not god who is the source of all truth but some evil mind, who is all powerful and cunning, has devoted all their energies to deceiving me." (22) And continuing he writes:
"setting aside everything which is subject to the least doubt as if I had had found that it was completely false. I will follow this strategy until I discover something that is certain or, at least, until I discover that it is certain only that nothing is certain….I will assume that everything else I see is false….I convinced myself that there is nothing at all in the world, no sky, no earth, no minds, no bodies." (23, 24)
So here is Descartes in his complete and utter state of doubt, that is, at least as far as he is able to doubt. But for all his doubt, Descartes finds that, no matter how hard he tries, there is one idea that he cannot doubt—the idea that he exists—and with respect to this he writes:
Is it not therefore true that I do not exist? However, I certainly did exist, if I convinced myself of something. There is some unidentified deceiver, however, all powerful and cunning, who is dedicated to deceiving me constantly, therefore, it is indubitable that I also exist, if he deceives me….This proposition ‘I am, I exist’ is necessarily true. (24)
This is Descartes’ starting point, and the base of all of the later knowledge that he is to consider supportable—his utter certainty that he exists—and this, his first principle, is "Cogito ergo sum," or "I think, therefore I am." In a later section of our examination of Descartes, we will address this claim, but for now, let us follow his logic.
Since Descartes is certain that he exists, then he feels confident that he can discover more truths and whether other things exist in addition to his own existence. And in his attempt to discover further knowledge, Descartes holds that his mind is the standard of all truth and certainty. Descartes’ 2nd assertion from his 1st principle is that truth lay in clarity and distinction, and that any idea that is necessarily true must present itself to the mind precisely as it really exists, so that there can be no chance of an erroneous, distorted or false notion or mental picture of that idea. Descartes held that to have a clear and distinct idea of something one must have a precise understanding of what it is that one has an idea of. Later, in our examination of the critics of Descartes’ claims, we will find that some of the philosophers that followed Descartes used this notion of clear and distinct ideas to stir up great controversy on many things including ideas that are held as sacred by followers of Christianity. For now, however, we will allow Descartes to present his case.
In his 3rd assertion, Descartes maintains that no being has, in itself, the explanation of its own existence, and since nothing can be the explanation of itself, then there must be some other explanation. As an imperfect being who has certainty of his own existence, Descartes maintains that this knowing, or certainty, is more perfect than doubting. But where did this notion of knowing being more perfect than doubting come from? Since we are imperfect, Descartes asserts, then, a perfect being must exist. And God must be that perfect being, and he must have implanted the idea of his perfection in our minds as an innate idea. In this way, our imperfect minds can know some things with certainty, and this ability must be a gift from God. And God, being perfect, cannot deceive us, and we can be certain that God exists, and that we can have certainty with respect to other things, and we can have confidence in the human understanding in general. Again, the readers are likely to have a bountiful collection of objections, but let us bear Descartes’ assertions for just a little longer, and defer our critiques to a later section of our study, and in politeness, allow Descartes to finish presenting his case.

IV. CARTESIAN DUALISM
At this point, Descartes is positively certain of two things—that he exists and that some absolutely perfect being exists, and Descartes uses the word "God" to denote this perfect being whose existence is guaranteed to the satisfaction of Descartes, having passed the scrutiny of his tests. These and only these two things are held as knowledge by Descartes at this junction of his voyage into the realm of human cognition.
To continue in his quest for even more knowledge that can be held with all certainty and beyond all doubt, Descartes finds it necessary to "suppose there is some very powerful and, if I may say so, evil deceiver who is committed to deceiving me in everything possible." (25) Proceeding from his indisputable certainty that he thinks and that he therefore exists, a frightening thought occurs to him. "I am, I exist. That is certain. But for how long? As long as I think, for it might possibly happen if I ceased completely to think that I would thereby cease to exist at all." (25) Exactly what is it then that he who thinks and therefore exists is? This is the next question that Descartes feels he must find the correct answer to. He is more than a mere collection of limbs, he thinks. And he, as a soul, is not a mere wind or gas or some such thing. "I am therefore, precisely only a thinking thing, that is, a mind soul, intellect or reason—words the meaning of which was formerly unknown to me. I am a thinking thing." (25) Descartes does not address the question of how he discovered language in the intellectual vacuum in which he claims to be conducting his experiment in human cognition. And without language it is doubtful that he would be able to think in such abstract terms because language gives us the ability to condense concepts into manageable units like words.
All previous philosophers and theologians held that a human being is a single unified entity, the form of which is a soul or a mind, and which, when combined with prime matter becomes a human being. But Descartes made a sharp distinction between the mind (soul) and the body. After some cogitation on the fact that wax, when subject to heat, changes in shape, volume and in other aspects that are usually considered properties, Descartes finds that "the wax itself" remains. To the modern reader this may seem to echo Plato’s notion of "the idea itself," or the form or essence of a thing that was said to exist independently from this world of particulars and properties. And for Descartes, "the soul itself" is said to exist independently from the body and independently from anything whatsoever that is related to the senses, just as something called wax exists even if all of its distinguishing characteristics are stripped away from "the wax itself" when heat is applied to it. And here we arrive at Descartes amazing new discovery—that he has a mind and a body—and that these two "substances" are separate and distinct from one another. Descartes claims that the body and the mind are two different "substances" and that they belong to two separate realms of existence. The body belongs to the material universe that we perceive, but the mind or soul belongs to a nonmaterial realm that has nothing to do with the physical world. The mind, he says, exists independently from the material universe as we know it.

V. DESCARTES’ IMPACT ON MODERN PHILOSOPHY AND SCIENCE
The philosophy of Descartes had a profound impact on the philosophers and theologians of his day. Descartes’ philosophy is said to have paved the way for modern science. Although he argued for gaining knowledge from reasoning alone, without experience through the senses, his philosophy had a different outcome. Later philosophers such as the Empiricists denied that there is any such nonmaterial realm and they denied Descartes’ assertion that there is a distinct substance existing independently from the senses or from the physical world. The Materialists argued that the universe is nothing more than matter in motion moving through space. They maintained that the mind is nothing more than a process of physical phenomena just as breathing and defecating are natural processes, and that there is no warrant for asserting the "the soul itself," as existing independently in some realm. Scientists like Galileo and Isaac Newton had the most penetrating minds, and they studied the physical world with intense passion. The scientific discoveries of these two men had a profound impact on philosophers and theologians. Their scientific findings seemed indisputable and cast severe doubt on the authenticity of religious scriptures that assert things that are known to be inaccurate and contrary to scientific knowledge. The motion of the earth around the sun is just one example of scientific discovery that infuriated the church, and scientists such as Galileo were imprisoned in the church dungeons for daring to discover things that run contrary to scripture. After Isaac Newton made his superior scientific discoveries, many philosophers found scripture to be utterly false and fantastic, while others hustled to find ways to interpret them in parabolic, figurative and poetic ways in the attempt to save religion from ruin in what came to be known as the age of reason. Thomas Woolston is one example of the many authors who were imprisoned and threatened for offering metaphorical and parabolic theological opinions of scripture.

VI. OBJECTIONS TO DESCARTES
Modern critics of Descartes cite the following objections against his principles, notions and assertions:
In Religion and Science, Bertrand Russell writes:
"Natural knowledge only enables us to recognize a thing by its attributes….Under Locke’s influence, his followers took a step upon which he did not venture: they denied the whole utility of the notion of substance….there is no need to suppose an entirely unknowable core, in which his attributes inhere like pins in a pin-cushion. What is absolutely and essentially unknowable cannot even be known to exist, and there is no point in supposing that it does….The conception of substance, as something having attributes, but distinct from any and all of them was…rejected by Hume, and has gradually been extruded both from psychology and from physics." (115, 116, 117)
Russell goes on to show how David Hume argued against Immanuel Kant’s spin on Descartes’ and Plato’s assertions of "things in themselves." Here is Russell’s take on this matter:
There is obviously some sense in which I am the same person as I was yesterday…if I see a man and hear him speaking, there is some sense in which the I that sees is the same as the I that hears. It thus came to be thought that, when I perceive anything, there is a relation between me and the thing: I who perceive am the "subject," and the thing perceived is the "object." Hume boldly denied that there was such thing as the subject, but this would never do. If there was no subject, what was it that was immortal…had free will…and was punished in hell? Kant…thought he found a way out…Things-in-themselves, according to Kant, are not in time and space [but] there is a real Self and a real thing-in-itself, neither of which can be observed. Why then, assume they exist? Because this is necessary for religion and morals. (119, 120)
Now, as for Descartes’ evil demon who spends all of his time traveling all over the world tricking people into forming incorrect opinions such as the belief that they exist, it is difficult to imagine that anyone really believes this kind of stuff in this modern age. But one need merely listen to any televangelist on the radio or television to find that millions of people still hold such notions. Evil demons, we are told, whisper falsehoods into our souls. Their goal is said to be to trick us into forming incorrect theological opinions about God and salvation, and anyone who fails to form correct opinions on theological points of debate is allegedly going to be punished in a supernatural furnace called hell after they have passed away. One modern writer offers relief to those who suffer from such notions of a malevolent universe. Nathaniel Branden, an expert psychologist and writer of many volumes of self-help books on self-esteem and psychological well-being writes:
A mind is healthy to the extent that its method of functioning is such as to provide man with the control over reality that the support and furtherance of his life require….Reason, the faculty that identifies and integrates the material provided by the senses, is man’s basic tool of survival…one must never attempt to fake reality…one must never attempt to subvert or sabotage the proper function of consciousness….a consciousness torn by conflict and divided against itself…is an unhealthy consciousness….no control is possible in a universe which, by one’s own concession, contains the supernatural, the miraculous and the causeless, a universe in which one is at the mercy of ghosts and demons…no control is possible if the universe is a haunted house. (Rand 40, 41, 42)
Philosophers before and after Descartes’ time argued against the notion of innate ideas. Thomas Aquinas went so far as to argue that if we had innate ideas of the existence of God, then proof of his existence would be irrelevant and faith would be impossible because we would have direct knowledge and experience of that God. John Locke, a superior philosopher of the seventeenth-century, also argued very effectively against innate ideas in his Essay Concerning Human Understanding. Earlier, we saw that Descartes maintained that to have a clear and distinct idea of something one must have a precise understanding of what it is that one has an idea of. Locke, a philosopher who claimed to be a Christian, used Descartes’ argument just mentioned in his rebuttal to a clergyman who was angry at Locke for writing The Reasonableness of Christianity, a book in which Locke uses scripture to show that in the Bible, no other belief distinguishes a believer from an unbeliever but this one belief only—the belief that Jesus is the Messiah, and that everyone who formed this one and only belief was "saved," with no other beliefs required whatsoever. The clergy was furious and accused Locke of posturing as a Christian while secretly being an atheist. Rev. Mr. Edwards, A clergy-man, denied Locke’s thesis on salvation in a series of pamphlets. In "Some Thoughts on the Causes and Occasions of Atheism, especially in the present Age," this clergyman argued that there were many beliefs required for salvation; not just one. For salvation, said the clergyman, one must believe in the "trinity." Locke used Descartes’ argument here—the argument that to have an idea of something or believe something, one must have a clear and distinct idea of what it is that is believed. Locke asked the clergyman if salvation requires that the believer have a clear and distinct idea of the exact nature of the "trinity," "transubstantiation," and other obscure creeds in order to obtain salvation. The clergyman maintained that absolutely everything the Bible is plain, evident and illustrious and that it cannot be read without being believed—a direct contradiction of his initial position at the beginning of his attack on Locke when he claimed that Christianity is divine mystery which is not always clear, etc.
Others criticize Descartes’ allegation that God must exist because Descartes has an idea of God in his mind even though he detached his mind from his senses. These critics point out that to hold such a position is to hold the position that thousands of gods must exist since thousands of different minds have ideas of thousands of different gods.
Many philosophers point out that Descartes smuggled a great deal of knowledge obtained from sense experience into his mind, regardless of his claims to have dispensed with all of his knowledge and detached his mind from his body.

VII. CONCLUSION
Descartes can be appreciated for suggesting that once in a lifetime we should all cast away our unexamined notions that we have previously taken uncritically, without question and held as knowledge. Descartes asks us to challenge all of those ideas and try to empty our minds of all preconceived notions and to act as neutral judges with respect to what is true. And for this we are indebted to Descartes because this is precisely what the philosophers and scientists did that followed him. Unlike Descartes, however, many scientists and philosophers did not end up discovering the existence of any innate ideas, gods or evil demons, though others tried to defend the possibility of such things. Some philosophers tried to rescue religion from science, and offered the hypothesis that there is nothing mysterious in the scriptures, and that there is nothing contrary or above reason in them. John Toland’s Christianity Not Mysterious, for example, is a case in point. But this would be to take away one of the theologians’ most useful arguments against those who pointed out contradictions in the scriptures, and the theologians simply would not have it. It was seen as imperative to hold onto the statement that those contradictions in the scriptures are divine mysteries which are above and beyond our ability to comprehend. Thomas Woolston, in his Six Discourses on the Miracles of Our Saviour, attempted to show that the scriptures ought to be interpreted metaphorically and poetically. Woolston dared to express his opinion that the resurrection and other biblical notions are merely metaphorical truths and that to interpret scripture literally leads to outright absurdities. This outraged the clergy. Woolston was conveniently fined, imprisoned and declared insane by the clergy.














List of Works Cited
Descartes, Rene. Meditations and Other Metaphysical Writings: London: Penguin Books, 2000
Locke, John. The Reasonableness of Christianity: London: John Hatchard and Son, Piccadilly 1836
Plato. The Republic. New York: Vintage Classics, 1991
Rand, Ayn and Nathaniel Branden. The Virtue of Selfishness: New York: Signet, 1964
Russell, Bertrand. Science and Religion: New York: Oxford University Press, 1961
Toland, John. Christianity Not Mysterious: Dublin, Ireland: Lilliput Press Ltd, 1997
Woolston, Thomas. Six Discourses on the Miracles of Our Saviour: New York and London: Garland Publishing, Inc. 1979