• From faith, we believe God to be the greatest entity.
• There are two ways to believe something: either it exists in reality, or it exists in our intellect.
• If God is the greatest entity, then it must exist in reality and in the intellect, than simply in the intellect alone.
• It is therefore contradictory to believe that God exists only in the intellect, for the greatest entity must exist both in reality and in the intellect.
• Therefore, God must exist in reality.

In the 12th century, the center of learning moved away from the monasteries and to the towns. Near Paris, Peter Abelard (1079-1144) founded a number of schools in order to explore the relationship between religion and philosophy. New methods of education were emerging during this time. These methods – known as scholasticism – placed far more emphasis on the exploration of dialectic and logic, than on simply adhering to tradition and custom. This new scholasticism created a complete Cultural Revolution. Around this same time, the works of Aristotle were being translated into Latin. Previously, only a few of his minor works were known. Now, with works such as Analytica Posteriora, Topica, and Analytica Priora, Aristotle’s methods of discussion and enquiry were reaching a wider audience. Many other texts from both the Greek and Arabic world were also translated. In Europe, this was to create a "knowledge" explosion.

18. Saint Thomas Aquinas (1225-74)
The most influential medieval philosopher was Saint Thomas Aquinas. For Aquinas, reason and faith cannot contradict each other, for they both come from the same divine source. Aquinas was the first philosopher to show the church that it was possible to incorporate many of the metaphysical and epistemological teachings of Aristotle. This was a great departure from the dominance that Neoplatonism had during the early medieval period. Aquinas believed that theology was a science. Careful application of reason will demonstrate the certainty of theoretical knowledge. For Aquinas, it was always preferable to support one’s belief with a rational argument. Aquinas objected to Anselm’s ontological proofs for the existence of God. Aquinas argued that since we are ignorant of the divine essence from which it began, we couldn’t even begin to demonstrate its necessary existence. Aquinas said that we must first begin with the sensory experiences that we do not understand. Then we should reason upward to locate their origins in something eternal. Aquinas formulated "five ways" to prove the existence of God. The first way is the argument from motion.

• From our sensory experience, we see that something is moving
• To move, something has to be moved, or put into motion, by something else
• The series of movements cannot reach back infinitely
• Therefore, there must be a first mover
• This mover must then be God

There are many objections that could be made regarding the above arguments. If the second statement is absolutely true, then the conclusion must be false. Why must there be a first mover? Couldn’t there be countless first movers? If a first mover did exist, why assume that it would resemble the God of Christianity? Even if the above ontological argument succeeded, it wouldn’t necessarily support orthodox religion. The 2nd way has the same structure as the 1st, but begins from experience of an instance of efficient causation. The 3rd argument relies heavily upon a distinction between contingent and necessary "being." The 4th way is based upon a moral argument. To make a moral argument, we make a distinction between what we "judge" and the standard to which we hold as an ideal. This argument relies heavily on Platonic Idealism. The 5th way is known as the Teleological Argument. The order and arrangement of the natural world implies the deliberate design and intention of an intelligent creator. Therefore, our existence must have meaning.

19. William Ockham (1285-1347)
By the 14th century, the views of Thomas Aquinas – Thomism – were called the "old way" of achieving philosophical knowledge. The "new way" or "modern way" began with William of Ockham, an English Franciscan who represented his Order in numerous controversies over papal authority. In his philosophy, he was primarily concerned that an over-emphasis on "universal" forms would undermine the theological doctrine of free will. Ockham, like his predecessors, wished to defend the Christian doctrine of the omnipotence and freedom of a divine being – God. For him, God’s freedom is incompatible with the existence of divine ideas. God doesn’t use preconceived "ideas" when he creates, but creates the universe as he wishes. Consequently, human beings have no natures or essences in common. The only reality is "individual" beings or things. These beings or things are unique, and have nothing in common. Only concrete individual substances, and their particular characteristics, are real for Ockham. There are similarities among these "individual" things – and we can categorize them – but they are still unique to each other. Because God is free, he can create the universe – and its rules – as he wishes. Fire could be cold rather than hot. Light might be dark, rather than bright. Ockham distrusted our ability to find the truth of things. Instead, he relied on "probable" arguments to support his position. A vital principle in his philosophical method was that "plurality is not to be posited without necessity." This economy of thought is often referred to as Ockham’s Razor. The views of William of Ockham spread widely in the late Middle Ages, despite being censured by a papal commission at Avignon in France.

20. The Collapse of Scholasticism
In the 14th and 15th centuries, the critical philosophy of Ockham began to undermine the scholastic project of synthesizing the traditions of philosophy and religion into a single and comprehensive system of thought. Many argued that the attempt to unite religion with philosophy had failed. Many prominent thinkers of the time – Jean Buridan (1300-1358), Nicholas of Autrecourt (1300-1350) – felt that such a synthesis wasn’t possible. Nicholas of Cusa (1401-1464), who deliberately embraced contradiction in trying to unite religion with philosophy made one final attempt. Cusa argued that if God’s perfect unity can encompass contradictory qualities, then the contradictions evident in the philosophical tradition should also be embraced in a single comprehensive whole. Its logical consistency was, therefore, unimportant.

21. The Renaissance
By the end of the 15th century, the cumulative achievements of scholasticism – the comprehensive body of philosophical work developed by numerous medieval scholars – were gradually being eroded. This work, based mostly upon a neoplatonic and Aristotelian foundation - and which was directed towards supporting traditional Christian theology - began to be undermined. Beginning with the Renaissance, philosophers began to move away from theology as a vital part of their work. The old authority of the Roman Catholic Church was weakening, and Renaissance thinkers felt that their role wasn’t simply to explain and complement divine revelation and scripture. Instead, there was a new focus: the individual. Just as many religious reformers had challenged ecclesiastical authority in the late medieval period, so too did Renaissance thinkers move away from institutional authorities in education and science. There was a renewed emphasis on individual freedom and choice. Many humanists of the Renaissance period, such as Giovanni Pico (1463-1494), expressed a profound confidence in the power of human reason to enable us to understand human nature, as well as our place in the "natural order." Philosophers such as Marsillio Ficino (1433-1499) and Desiderius Erasmus (1466-1536), rejecting the numerous commentaries written by the scholastics, returned once again to the study of ancient classical texts. Other humanists, such as Francisco Suárez (1548-1617) and Giordano Bruno (1548-1600), attempted to create entirely new metaphysical systems by incorporating these classical texts with modern developments of the period. These philosophers were also very different from their predecessors in that their thinking was directly related to their national origins. The philosophy of Niccoló Machiavelli (1469-1527) was directly related to the political climate in Italy. Likewise, the philosophies of Francis Bacon (1561-11441626 and Thomas Hobbes (1588-1679) had a direct connection with English life. This was very different from the philosophers of the medieval period. The works of Thomas Aquinas (1225-1274), Albertus Magnus (1200-1280), and St. Bionaventure (1221-1274) were unrelated to the country of their birth, and was more directly connected to their positions in the ecclesiastical hierarchy.

The Renaissance period also placed a greater emphasis on using empirical methods for attaining knowledge. Copernicus (1473-1543) created a theoretical foundation for a heliocentric view of the universe. Kepler (1571-1630) later added the mathematical structure to support the heliocentric view. During the same period, Galileo (1564-1642) documented numerous direct observations of terrestrial and celestial motion. By emphasizing the importance of direct observation, Renaissance thinkers created the foundation for a completely empirical view of the world, a view of the world that was completely new. This "new science" coincided with – and was made possible by – new advances in instrumentation and optics. Without these tools, an accurate empirical study could not have been made. A number of other inventions, taken from the East, were to completely transform Europe in the 15th century: gunpowder, block printing, and the compass. Gunpowder became an agent of the new spirit of nationalism. It was used to destroy the massive fortifications of the old feudal order, thereby threatening the rule of the churchmen. The advent of the printing press also enabled the spread of knowledge throughout Europe, thereby ending the monopoly of the ecclesiastical elite. Classics in philosophy and literature were reaching a wider audience, and with it new questions. Because of the invention of the compass, it was also now possible to navigate safely at huge distances. This facilitated the entry into the Western Hemisphere.

But the "empirical view of reality" did have its critics. In translating and studying the ancient classical texts, the humanist scholars came upon the work of Sextus Empiricus (3rd Century A.D.), who introduced the philosophical concept of skepticism and the limits of human knowledge back into the debate. Michel de Montaigne (1533-1592) was one of the most prominent exponents of the skeptical view. Montaigne believed that we were arrogant in believing that we could attain a complete and accurate view of the natural world. Why should it be there for our benefit? Why do we believe that we should understand it at all? Wasn’t it arrogant to believe that we were meant to understand it? His argument rested upon a number of assumptions:

• Our senses are unreliable, and therefore prone to error
• Logical reasoning cannot be demonstrated without circularity, therefore logical reasoning is not reliable
• We should, therefore, doubt everything and settle for "mere opinion"
• The "new science" can offer us no hope. Everything new is eventually surpassed

In responding to the challenges put forward by Sextus Empiricus and Montaigne, philosophers defined four distinct areas of philosophical enquiry: metaphilosophy, ethics, metaphysics, and epistemology. It was within these four areas of enquiry that many of the later philosophers addressed themselves.

Metaphilosophy
What is the purpose of philosophy? Does it have a place, generally, in human life?

Ethics
How do we judge and evaluate human behavior? What is "the good" and what motivates our moral actions? Without the support of religious belief, is a moral life possible?

Metaphysics
Does God exist? What is the universe made of? What is the meaning and purpose of the universe? Why are we in the universe, and what is our purpose?

Epistemology
Is certain knowledge of the world possible? What does it depend upon?

In addition to the above four areas of enquiry, there arose three special categories of philosophical interest: political philosophy, humanism, and the philosophy of nature.

22. Political Philosophy
When secular authority replaced ecclesiastical authority as the dominant focus of interest, there was a shift of attention from religion to politics. Ideas that had lain dormant since pre-Christian times, concerning the nature and moral status of political power, were now renewed. Political philosophy, particularly in England, France, Italy, and Holland, began to flourish. But political philosophy during the Renaissance was essentially dualistic. It recognized a conflict between two opposing points of view: political necessity and general moral responsibility. Many philosophers of the time, including Machiavelli and Hobbes, attempted to resolve the conflict between these two positions. Both struggled with the conflict between institutional power and human freedom. By different means, they both concluded that only with a strong institutional base could morality flourish.

23. Niccoló Machiavelli (1469-1527)
Niccoló Machiavelli, early in the 16th century, wrote one of the most influential books on political philosophy: The Prince. Machiavelli, once a state secretary of the Florentine republic, resigned his position in order to write about political philosophy. His work primarily explored ways in which political power could be seized and maintained by the state. On initially reading his work, the impression is given that his main concern is solely with maintaining the power of the state, with little regard for the moral consequences of doing so. The term "Machiavellian" is often used in present times to refer to someone who is politically deceitful and unscrupulous. But this is a mischaracterization of his real attitude towards morality. For Machiavelli, the unification of Italy was of prime importance. In order to make this unification possible, he believed that only a strong state – based upon the ancient Roman virtues – could provide the proper environment for morality to flourish. The Prince, published in 1513, offered practical advice on how to rule. The successful Prince, it maintained, must demonstrate virtú – skill or prowess – in both favorable and unfavorable times. Unlike the ethical philosophers, Machiavelli held that success in the public arena was distinct from private morality. The question, for Machiavelli, is not what make a human being good, but what makes him a good prince. A good prince will use any means necessary in order to create the foundations of a stable state.

24. Thomas Hobbes (1588-1679)
A century later, Thomas Hobbes – tutor to Charles II - proposed the idea of a "social contract." Hobbes believed that the life of man in the "state of nature" was "solitary, poor, nasty, brutish, and short." In this brutish world, which preceded civilized social structures, "every man’s hand" was "raised against every other." Thus, in order to live in a civilized world, it was necessary to create a "social contract." Within this social contract, we would be expected to surrender our individual rights in order to benefit from the security of a stable society. This "commonwealth" would provide the environment for liberty, freedom, cooperation, and contentment. According to Hobbes, the formation of the commonwealth would create a new entity: the Leviathan. It was to the Leviathan that complete responsibility for social order and public welfare was entrusted. But who would embody the role of the Leviathan? Hobbes proposed that all private rights should be subservient to that of a single authority. In return for this, private citizens would expect to receive general protection, as well as the rule of law. In Hobbes’s view, the Leviathan could be a legislature, a single human being, or even an assembly of citizens. But Hobbes maintained that the best choice would be a hereditary monarch. By investing power in such a stable institution as the monarchy, we would protect our rights, collectively, as citizens. It was only when the sovereign failed to keep the commonwealth united, and to protect it, that his authority could legitimately be called into question.
In addition to his political philosophy, Hobbes is also credited with the creation of one of the most comprehensive philosophical systems of the time. His philosophy – which is usually labeled as mechanistic materialism – sought to provide a consistent description of man, nature, and society. It had much in common with the views of the early Greek Atomists. Hobbes distinguished between two philosophical approaches: synthetic and analytic. When we reason "forward" from causes to effects, we are reasoning synthetically. And when we reason "backward" from effects to causes, we are reasoning analytically. Hobbes also distinguished between "content" and "method." The philosophical questions we choose to pursue are matters of "content." The reasoning and language we use to address these questions is referred to as the "method." In addition, Hobbes’s study of language led him to adopt a nominalistic position. Nominalism denies the reality of universals.

Hobbes’s metaphysical foundation was that "reality" is matter in motion. The real world of our senses in located within a universe of constant movement and change. Therefore, the task of philosophy was to trace the causes and effects of these movements and their "effects" upon our minds. Hobbes classified three main areas of study:

Physics
The science of actions and motions on natural bodies

Moral philosophy
The study of "the passions and perturbations of the mind" and how it is "moved" by appetite, desire, envy, or fear

Political or civil philosophy
How our chaotic behavior is constrained and guided by a force or power in order to create peace and prevent civil disorder

25. René Descartes (1596-1650)
The most significant philosopher of the late 17th century was René Descartes. He was a French citizen, but wrote his most productive work in Holland, which was very tolerant of new ideas. Descartes was educated in the scholastic tradition, but his pursuit of both mathematical and scientific truth eventually led him away from that tradition. His primary concern was with the creation of a secure foundation for the development and advancement of human knowledge. Descartes is considered to be the father of what we call Modern Philosophy. His ability to synthesis philosophical influences from the past, with the revolutionary advances now taking place in science, singled him out as one of the most influential and dominant philosophers of his time. In creating his "Cartesian" philosophy, he drew heavily upon earlier philosophers. From Aquinas and Anselm, he incorporated theological questions into his work. From the ancient Skeptics – Sextus Empiricus and Pyrrho – he formulated a new and revitalized skepticism. He was also heavily influenced by both the ancient Stoics, as well as with the work of Augustine.

As well as being a great philosopher, Descartes was an exceptional mathematician, and was the inventor of analytic geometry. Mathematical logic and reasoning played an important role in his philosophical studies. Descartes is considered, along with Francis Bacon (1561-1626), to be a founder of modern Empiricism and Rationalism. Descartes defined philosophy, in his Principia, as the "study of wisdom or the perfect knowledge of all one can know." In explaining the relationship between philosophy and our lives, he used the metaphor of the tree. The root of this tree is metaphysics. The trunk is physics, while the branches are morals, mechanics, and medicine. Descartes primary concern was with the trunk of the tree, which represented physics. In fact, unlike Aristotle – who attempted to create a metaphysics upon physics, Descartes did the opposite. He attempted to create a "physics" build upon a "metaphysical" foundation.

Descartes can also be credited with introducing dualism into our philosophical speculations. This dualism took two forms: the first was between God and the material world. The second was between the material world and the mind.

Descartes employed three distinct methods to build his philosophy. These were as follows:

Skepticism
To systematically question and doubt every belief that does not pass the test of indubitability

Subjectivism
To base all knowledge upon a foundation of certainty. For Descartes, consciousness, and in particular self-consciousness was that foundation. As such, "I think, therefore I am" emerges as the only innate belief that is unshakable by doubt. In fact, we can never to absolutely sure of the existence of the world as we can of our own existence. Therefore, the task of the philosopher is to study the mind, for only the mind can get to the truth underlying the everyday appearance of things. This had much in common with Platonic idealism

Mathematicism
To reject any idea that is not concise, clear, and free of contradiction

These can be alternatively stated as:

• Only those things which are indubitable are true
• Every question should be divided into manageable parts
• Start with the simple, and build towards the complex
• Frequently review the entire argument for consistency

Though the above stated principles lay a very firm foundation for philosophical enquiry and progress, it must be remembered that Descartes was also a good Catholic. As such, he did not apply his own principle of radical doubt to his own religious beliefs. This led to numerous self-contradictory positions in his philosophical work. Though he profoundly respected Galileo’s writings, he chose to withdraw his own cosmological treatise, Le Monde (The World), from publication when the Inquisition condemned Galileo, in 1633. Descartes understood that his methods were radical, and hence a threat to the church. These concerns aside, he was strongly influenced by his religious faith.

The duality that existed between his religious beliefs and his scientific empiricism were evident from the very beginning. For example, Descartes stated that animals were complicated machines, but they had no soul. They are "clockwork" creatures. But how do we know, as human beings, that we are not also "clockwork" creatures? Descartes replied that "I know I have a soul" because "I think, therefore I am." From this assumption, he concluded that a perfect god must exist. His argument was as follows:

• I know that I exist
• Since I am not perfect, I could not be the cause of my own existence
• Something must have caused my existence because I exist
• Whatever caused me must have also have a cause
• The chain of causes must eventually end with a first cause
• This first cause must be a perfect entity, a self-caused being
• This entity must be God
• God, being a perfect entity, would have no reason to deceive me
• I can therefore conclude that my search for truth is a noble and attainable one, since a perfect entity created me
  The problems with the above chain-of-reasoning are numerous. The first is that it uses a circular argument to prove the existence of God. Descartes first uses the existence of God to say that it is rational to assume the reliability of clear and distinct ideas. He then uses these very same "reliable" ideas to prove the existence of God. Descartes responded to this criticism by stating that his argument wasn’t circular because "intuitive" reasoning, in the proof of God’s existence, requires no additional support in the moment of its conception. The problem with this reply is very significant. The attempt to prove the existence of God is Descartes first challenge after he has first stated that "I think, therefore I am." If this first effort should be flawed in its approach, then it follows that every other conclusion should become questionable.

Though Descartes may not have adhered entirely to the principles of radical doubt he had previously outlined, his influence was great in the 17th century. Even though Scholasticism was still being taught in the universities, it was Cartesianism that dominated intellectual life in Europe. Despite Descartes efforts to respect his theological convictions, it was inevitable, because of his popularity, that his work should come under scrutiny by church authorities. The Roman Catholic Church, in 1663, placed many of his writings on the Index of Forbidden Books. Academia consequently banned the teaching of his philosophy. But there was one exception: the Dutch universities. In Utrecht and Groningen, Cartesianism thrived in the free and tolerant atmosphere. It was in this setting that Cartesian principles were further developed, principles which were to have a radical effect on philosophy to this day.