"Table of Contents"


   Experiencing the Humanities


A Web Textbook

CollegeHumanities.org,  or  OnlineHumanities.org




7. The Rise of
Enlightened Reason



Portrait of French philosopher Renee Descartes*


Chapter Seven of

Experiencing the Humanities

by Richard Jewell

Introduction--The Age of Reason in the West

The Western Enlightenment of the 1700s and the Reformation of the 1500s and 1600s before it were, in their broadest sense, a period of Western history when the Roman Catholic Church broke into a number of different Protestant churches and several Roman Catholic factions, and a middle class also rose up from almost no existence at all in the earlier 1300s-1600s. These middle classes--small-business people--began to seek political rights, as well as education. During this period, as well, because these middle classes began to have leisure time, they also began to seek out the arts and the pursuit of thinking on their own, without being told by the Church what to believe.

In philosophy and theology, part of the Enlightenment was to reject the idea that religion--and belief in God--were a priori starting points for developing a belief system. "A priori" means "innate," "basic," or "coming first--before one's own experience." The earlier theologians of medieval times believed that there were innate qualities or beliefs--such as belief in God and the existence of a soul in humans--that were a priori true. These a priori beliefs did not need proving. They were self-evident or evident through faith. However, with the coming of the Enlightenment, complete acceptance of a priori religious truths began to fail. People began to look more at logic, human thinking, and especially reasoning as being more worthy of study than had been the case since the Greek and Roman philosophers before Christianity and Islam began to dominate the West.

Thus it was that "reason" began to replace "revelation" in philosophical thinking. "Reason" meant scientific, logical, thinking using one's mind. This was opposed to "revelation," which meant the revealed word of God in scripture. Eventually many parts of Christianity and Islam came to accept reason, as well. But this was not always true. Science and reason had to fight for their importance initially.

For example, famous astronomer Galileo, born in 1664 and sometimes described as the creator of modern science, championed the view of the universe that the planets revolved around the sun. He was perhaps the most famous scientist of his time. Unfortunately, for a thousand years and more, most people--including scholars--believed that the sun, the planets, and all the stars revolved around the earth. He pushed his beliefs too hard, and in the 1630s he was condemned for suspicion of heresy by the Inquisition. He was forced to recant his belief, and he spent the rest of his years, until his death in 1642, under house arrest.

However, as people became more independent from old ways of thinking, more able to read, and more curious about life, scientific thinking began to find greater acceptance. By the 1700s this blossomed into the Enlightenment in the West, which sometimes is called the Age of Reason.

Scientific Thinking

Scientific thinking led to empiricist, naturalist, and materialist forms of philosophy. The empiricists said that real knowledge is based on experience. The naturalists said that real knowledge is based on the natural sciences. And the materialists said that everything is matter, and real knowledge is based on the study of matter. All three of these approaches emphasized reason and scientific thinking--and took away the central role of revelation and theology in interpreting people's lives, feelings, thoughts, and awareness. 

The time of the Enlightenment also was a time of rediscovery of the Greek philosophers. Most of the Greek philosophers, who lived before the influence of Christianity and Islam swept the West, did not start philosophizing from a religious base of belief.

These ancient Greek philosophers seemed to believe in figuring out things for themselves, rather than depending on belief in the gods. It was important to the early Greek philosophers to use reason in the search for truth. The late medieval thinkers, in a whirlwind of new and contradictory ideas about the role and meaning of a central church and its moral and theological beliefs, took note of these Greek philosophers and their quests for meaning using reason as a tool.

For perhaps a thousand years, for example, physicians did not open people's bodies to see what lay inside. In the 1600s, English physician William Harvey began opening people up and examining them--a thing repugnant to most physicians of the time. What he found inside sometimes was different than what Aristotle and his later interpreters had said was there. Medical science was reborn based on the principle of looking and learning--of finding out for oneself what is there by rational observation--rather than just trusting one-thousand-year-old experts. 

This same revolution was happening in other fields of science, too. An age of reason was dawning, and this had a deep affect on philosophers of the age.

I Think--Therefore I Am

One of the first modern philosophers of reason was Rene Descartes. A Frenchman, he lived from 1596 through 1650 and sometimes is called the father of modern philosophy. He and Isaac Newton often are considered the two most important founders of the Enlightenment.

Descartes' primary contribution to philosophy was to throw out all necessary a priori beliefs in a God or religion and simply examine the evidence of our senses and life experiences. He said that all philosophizing starts with this principle:

"I think, therefore I am." or "Cogito ergo sum" (Latin).

This was a radical idea: First, it turned away from the Church and religion and toward the individual in developing the start of a philosophy of life. And second, it did not say that divine being was the first principle, but rather that thinking or being humanly aware was the first principle--that God did not come first, but rather observation and reason came first. There were people who thought Descartes should be killed for his philosophy because it came directly from the devil. Such detractors did not care that Descartes used his philosophy to explain that God, too, existed: the fact that his very first principal of philosophy was based on human perception made him a dangerous man to many thinkers of the time. 

In fact, at one point Descartes had even readied a book for publication, The World, which supported, among other things, the Copernican belief that the planets revolve around the sun. However, when Galileo was condemned by the Inquisition in 1634, this Copernican belief was forbidden. Descartes wisely did not publish his own book supporting this belief.

However, he did go on to publish other works, two of the most important of which were the Discourses and the Meditations. It was in these and others in which he tried to create a perfectly rational philosophy, free of all false assumptions. He did include belief in God in his system--which, he claimed, could be rationally arrived at with proper observation of our thinking.

However, the die was cast by Descartes and by many others of his time, and the revolution of reason survived and grew. More rationalists came, and among philosophers three names were especially important:

Bacon (1561-1626; English)
Spinoza (1632-1677; Dutch/Jewish)
Voltaire (1694-1778; French)

Each of them advanced the theory of and belief in reason, sometimes connected to God and sometimes not, but always in itself primary.

Francis Bacon is considered the forerunner of the British empiricist movement (Locke, Hume, J.S. Mill, Russell). He separated reason and revelation and believed deeply in the scientific revolution's power to bring utopian good to society. He also believed that many philosophical positions really were irrational positions that got in the way of rational knowledge.

Benedictus (or Baruch) de Spinoza was so much a nonreligious philosopher that he was expelled from his Jewish community for heresy. Christian theologians later attacked his works and got some of his writings banned. Spinoza believed, as did Descartes, that everything we know can be logically or rationally deduced from a few basic principles. Spinoza did not believe in a personal God, but he did believe that there is a sense in which God is inside of, or with, everything--so that all of creation is also God. This was a form of pantheism. Freedom, for Spinoza, existed insofar as a person could learn to overcome his or her passions or emotions and follow a life of reason.

Voltaire, a pen name for Francois Marie Arouet, was one of the major French figures of the Enlightenment. Voltaire believed in God, but otherwise he was anti- Christian and, in particular, disliked the clergy. He was an early version of today's political grassroots liberal: he believed in the elevation of the middle classes, fair taxation for all, no special privileges for the rich, and strong support for both the arts and the sciences. He believed that the world contained both good and evil and that we must act strongly and certainly if we want good to prevail. He was considered a dangerous radical by many. His philosophical thinking was influenced by the English philosopher Locke.

This development of reason instead of revelation as a basis for philosophizing continued in new forms. No longer could a philosopher say, "God exists," and then continue from there. No matter what he or she believed, he had to explain the purpose and uses of rational thinking in any kind of philosophizing.

Instincts and Feelings

One reaction to the pre-eminence of reason was to reassert the importance of instinct and feeling: if religion could be thrown out the window, argued some philosophers, so could reason. And, argued these philsophers, even if we decide to keep reason as part of our philosophy or way of life, still we should give equal consideration to other human traits such as instinct and feeling. If, they argued, we are all basically intelligent animals, then our animal make-up must be as nearly important as--or more so than--our rational make- up.

This is what Jean-Jacques Rousseau (1712-78) did as part of the Romantic revolution against reason. He was one of the chief spokesman of this revolution. Romanticism was a reaction against the rationalism and empiricism of the Enlightenment. It declared the importance of the imagination, art, selfhood, and the transcendental. "Instinct and feeling are more trustworthy than reason," Rousseau wrote.

Rousseau and the Romantics were fighting against the commonly held belief of their time that religious, royal, or monied rulers should make enlightened choices for people beneath them, using reason as a guide. Rousseau developed the concept that society as a whole--all the people in a society--have a general will; and this general will is what should govern in any society. This way of governing, said Rousseau, will lead to what is in everyone's ultimate interest--this will establishes what is for the common good.

The Romantics were interested in the French and American revolutions as they developed. And in fact our modern democracies have adopted concepts like those of Rousseau in that we govern ourselves by using voting to determine what is the will the the people. Such voting is believed to be best for everyone in the long run, even for those on the losing side. In matters of business, however, our Western society still often follows the older model of governing by having one person or a small group use reason to make decisions that affect many people underneath them.

In a way, the Romantics were a counterbalance or opposite reaction to what may have been too great a weighing of the human scale toward rationalism during the Englightenment and afterward. The Church may have imposed belief and theology (and the royalty may have imposed worldly decisions) from the top down for a thousand years. However, during these thousand years both church and state had learned to serve and deal with two masters within the human being--the rational and the non-rational. The rationalism of the Enlightenment asked for more devotion to reason, perhaps, than the great majority of human beings are willing to give. The non-rational was not served, and the Romantics were perhaps part of a swing back to more centrist philosophical inquiry.

The Terrible Trio of Britain

Once the theology of the Church and, in fact, of any religious beliefs had been questioned, the door was opened wide for the kind of questioning that had not been seen to any large degree among thinkers since the end of the golden age of Greece.

If matters spiritual could be questioned, then why not question reason, too? And if reason could be questioned, why not also question our instincts and feelings?

Thus the direction of philosophy continued to move toward areas not thoroughly questioned or discussed since the Greek philosophers. Some philosophers began to question neither reason nor instinct and feeling, but the very process of perception and knowing. They asked how we perceive external objects and internal feelings and thoughts--and even whether or not our knowing is real.

Descartes had said, "I think, therefore I am." Other philosophers took this one step further and asked, "How do I know that I think?"--and "How do I know that I know?"

Three philosophers in particular in Great Britain were part of this deeper questioning. We might even call them the Terrible Trio because, as a group, they espoused belief systems that cancelled each other out--all in the name of defining how we can or cannot perceive reality. These three were:

John Locke (English, 1632-1704) Bishop George Berkeley (Irish, 1685-1753) David Hume (Scottish, 1711-1776)

Their three philosophies of perception essentially argued these three positions:

Locke: Matter creates mind.
Berkeley: Mind creates matter.
Hume: Mind and matter create each other.

The importance of their contribution lies not in their disagreements but rather in the intense beam of light they focused on the nature of our human perception and knowing. They were, in a sense, the first moderns in the field of present-day philosophy where knowing--and knowing how we know--have become predominant concerns.

Let's look briefly at each of them in turn.

John Locke was, possibly, England's most important philosopher. An empiricist, his philosophical thinking was partly responsible for the development of liberal democracy. He also was a leading exponent for the belief that material things are made of little particles or atoms. He read Rene Descartes thoroughly, travelled extensively and met many scientists, and held several important government and educational positions in his lifetime. Isaac Newton was among his friends.

Locke rejected the old medieval God-centered philosophies, but also found Descartes' rational explanations too limiting. Descartes believed that the mind is not a blank page, and some things are self-evident without any experience to prove them to us. For example, God, human thinking, and a rational, ordered world all were self-evident to Descartes. They were a priori true-- that is, what comes before experience.

Locke believed this was not enough. He, and later Hume, believed that all things are known only "a posteriori"--that is, they were what comes afterm as a result of, or from experience. All knowledge without exception, according to Locke, comes from experience. The mind, he says, is "white paper, void of all characters." Knowledge is transferred from reality to the mind. People do not and cannot have innate (a priori) knowledge of any kinds of truths. Knowledge from experience (a posteriori knowledge) is all.

Locke also believed that the existence of God was provable through intuitively true steps of logic, and he believed that there should be freedom of religion and of politics except when such activities infringed upon the freedom of others. Locke was well established in the more avant-garde thinking of his time, mildly radical, but ultimately both very acceptable and very successful among his peers.

George Berkeley was a philosopher of an entirely different color. Berkeley was educated at Dublin's famous Trinity College, became a Dean, and eventually was appointed Bishop of Cloyne. Berkeley reacted to Locke by turning the world of Locke on its head.

There is a famous question in philosophy that asks, "If a tree falls in a forest and no one is there to hear it, does it make a sound?" Berkeley answered this with a resounding "No!"

In fact, Berkeley went another step. According to him, if no one is there to hear or see the tree and the forest, then they do not exist. In other words, nothing exists except in the mind of the beholder. Berkeley says that "all those bodies which compose...the world have not any subsistence without a mind;...so long as they are not actually perceived by me...or any other created spirit, they must either have no existence at all, or else subsist in the mind of some eternal spirit. "

Thus Berkeley believed that things have no reality except as they exist in the mind of human or animal. However, he did agree that things humans or animals do not see might exist in God's mind.

One of Berkeley's main purposes, as he saw it, was to combat what he saw as rampant materialism. He wanted people to see "an all-wise Spirit, who fashions, regulates, and sustains the whole system of being" as being in the center of questions about reality. He did not want people to believe, as did the new class of developing scientists, in a material world made of Locke's atoms, a world entirely separate from God. Instead, he wanted all of reality to be seen as a vision or dream by God, and he wanted human beings to be seen as co-watchers and helpers--theater goers in the great cinema adventure produced by God and directed by humans, who were his most important creation.

Berkeley's main ideas found very little serious acceptance. However, he added to philosophical and psychological thinking in his detailed writings about how and what humans perceive and think. Though his conclusions were radical, his method was not: he was yet one more philosopher who focused the drama of human meaning on human perception, rather than on religious beliefs alone.

David Hume was a third British player in the philosophy of reason. He was a well-to-do and a very well-liked Scotsman. He was famous in his own time for his history writing, and he helped to develop the philosophical thinking beyond much of the American revolution and of political systems of democracy.

Hume was able to find a sort of marriage of convenience between the two nearly opposite positions of Locke and Berkeley. Hume probably was not so much influenced by Berkeley. However, Hume's concerns were to some extent like Berkeley's: Hume felt, as did Berkeley, that we cannot trust in sensory experience, alone, to determine what is real and true. Hume believed that human minds tend to have only unscientific impressions of what is real and true, and that humans then tend to project those impressions onto reality. For example, if you see two people in a fight, you might see them in a number of different ways, depending on who you are or even what day or time you see the fight, because your emotional feelings about them--or your past experiences of fighting or of seeing other fights--might cause you to see the fight in an entirely different way that would someone else.

Hume said that we can know nothing a priori, not even that nature itself is real as we see it with our eyes. There is, he believed, some kind of reality that exists, and that there also is, from our growing up and learning things, a variety of psychological impressions about what makes up reality. However, Hume said, we can never know the exact reality outside of us, nor the exact truth inside of us. This, he said, is because we cannot perceive matter exactly as it is; and as for a person's mind, it is nothing in and of itself, but instead is just a series of impressions--some more true and some less true--that together we label with the abstract word "mind." For these reasons, said Hume, we must be very careful in judging what, exactly, causes what. We must continue to examine not only our sense impressions of reality outside of us, but also our own mental perceptions of how we think, imagine, and remember. Somewhere in this mix of mind and matter, said Hume, we can begin to perceive what is rational and logical. 

As part of his philosophy, Hume also was very much an agnostic. He doubted God because he did not think there were any sufficient proofs of God's existence.

So, with Hume--and with other philosophers examining reason, reality, and the mind--the scientific achievements and rationalism of the world had turned very far away from a priori religious beliefs. This turn was so great that in the 1700s, among some scholars in larger cities in the West,  agnosticism even became acceptable. Certainly such beliefs did not dominate among most people in most countries. However, just that such people were allowed to live, write, and teach--to not be imprisoned or killed for their beliefs--was a huge change for scholarly thinking and for society and culture in the West.

Essentially, for future scholarly thinking and for philosophy, the so-called terrible trio of British thinkers--Hume, Berkeley, and Locke--had destroyed belief in anything and everything. Berkeley had said there was no real "matter"; and there was no real "mind," either, according to Locke and Hume. As one wit said ironically in dismissing the controversy, "Never mind, no matter."

Kant--Tower of Modern Philosophy

Thus it is that we come to Immanuel Kant (1724-1804), the great German philosopher whose philosophy is considered by many to be the most important watershed of the last several hundred years of philosophy. He also was directly responsible for the later philosophy of Georg Wilhelm Friedrich Hegel, whose philosophy led to the creation of communism, even though Kant himself was not a communist.

Kant was a major player in this history of the evolution of philosophies of mind and matter because he took the rationalist strains of such thinkers as Voltaire, Locke, and Hume, and combined them with the anti-rationalist transcendentalist tendencies of Rousseau and traditional religious philosophies of medieval times. When Kant brought everything together, the result was much of what the entire world now believes. So strongly has his influence been felt for two hundred years that it is said that one can philosophize for Kant or against him, but not without him.

Kant was born in Konigsberg, Prussia and stayed there his whole life. He first was a student and later a teacher at the University that was there. A life-long bachelor, so regular was he in his habits that the local residents would set their clocks by his daily walk. He wrote his masterworks later in his life: Critique of Pure Reason, Critique of Practical Reason, and Critique of Judgment. So dense are their thoughts--with a constant flow of very closely reasoned ideas--that some readers have declared themselves in danger of going insane from trying to read everything Kant wrote.

Kant wanted to return metaphysics--the study of ultimates and of being--back to the place of eminence it had enjoyed in the times before rational and logical philosophies appeared. However, he wished to do so without sacrificing all the discoveries that the new sciences were contributing. The "Pure Reason" of the title of his first Critique means a priori reason--what we can know of reason before, or unrelated to, experience.

Kant started his journey back to metaphysics by proposing that the very way we think has, in and of itself, certain basic structures or realities. He believed that raw sense experience is just simply that: raw sense experience. It is nothing more--not until we start thinking about it. Our eyes perceive raw material impressions; it is our minds that make this unsorted sense data into true objects, into things that we can comprehend and understand. In other words, our eyes see a collection or arrangement of materials; however, it is our minds that tell us, "These sensory data are what we call a 'chair,' a 'room,' and a 'human being.'" This is, in fact, very much like our popular concept of perception in present times. 

Kant said that there are twelve concepts or "categories" that the mind does not learn from experience but rather are known by us a priori. These categories are part of the a priori reality of mind. They are basic ways of seeing or understanding things and include the ability to perceive quantity, quality, relation, and modality. For example, when you see the difference between one object, several of them, or a large number of them, Kant says this has nothing to do with reasoning, but rather is because this automatically is part of every human mind. Likewise, if you see one object on your left and two on your right, and all three of them are different from each other, this is not reasoning but rather just an innate part of how your mind thinks. Your mind automatically creates these categories as you perceive and think.

Thus for Kant the mind was very real--without reference to the material world. Its reality is in its categories, and these are separate from--apart from--the physical reality of matter. He also believed that the material world is very real, even if our senses are inadequate for seeing to the core of the physical interactions of matter. To get an idea of where humans stand in reality, according to Kant, and what they can perceive, we can draw a line as follows. To the left is raw reality in its atomic nature. To the right is God. Humans, according to Kant, only can perceive what is somewhere in the middle.

Again, this is very much like our present-day popular views of where human perception fits on the continuum of reality. We know, for example, that there are types of energy--infrared radio, television, computer, and microwaves, for example--that we can't perceive, but almost all people believe they exist. At the other end of the continuum, said Kant, we are unable to perceive God.

Kant arrived at belief in God by taking what was for philosophers at that time a rather unusual turn down a new road, or at least new for the Age of Reason. He did not try to justify God from reasoning, or destroy belief in God using reason. In fact, he said that pure reason alone was in no way at all capable of proving the existence of God. However, he also said that reason cannot disprove God, either. Instead, he argued that reason alone was not enough to decide anything about God's existence. Instead, Kant turned to moral belief to explain why God exists.

Kant did this by saying that one of the experiences or feelings we have, one that is common to us as human beings, is the will or desire to be good or to do good. Kant added that this will or desire to do good is evidence of a "categorical imperative": a universal, a priori need or requirement to do what is moral.

Kant argued that because this categorical imperative to do good is universal, there must be a God behind it. And again, said Kant, though we cannot scientifically prove it, our feelings tell us with an absolute strength of conviction that we are deathless--that we survive death in some way. If there is such immortality, said Kant, then there must be an author or creator of this immortality. that author or creator, said, Kant, is God.

So, like Rousseau before him, Kant argued that we must listen equally to the voice of feeling within us. This voice of feeling, he wrote, has its own imperative, its own reality, which can deliver knowledge to us as certainly as the voice of pure reason. Kant was reviled for depending on feeling, alone, to justify God's existence. He was asked to stop his teachings about God because many considered them heretical. But his writings already had been circulated, and they changed the face of philosophy--and eventually of the world--forever.

Thus it has been, since the time of Kant, that few philosophers try to justify belief in God by arguing it using reason. In other words, after Kant, most serious arguments about belief in God have been based on the human life of feeling--not the life of reason. Feeling has become the standard. Through the 1800s and early 1900s, a variety of philosophers appealed to the life of feeling to explain the existence of God. Examples include existentialist Soren Kierkegaard's "leap of faith," Transcendentalist Ralph Waldo Emerson's feeling of God's presence in nature, and psychologist William James' argument that because so many intelligent people have claimed to have felt a spiritual experience, God must exist in some form.


In this way philosophy in the West arrived at our own more recent times. In the most recent centuries, philosophers have developed such major movements as existentialism, phenomenology, process theory, and others.

However, the really giant shift in Western philosophy came at the end of the long medieval period. Before then, you started any kind of argument by saying first that, a priori (of and in itself, unquestionably), God exists, and everything streams downward toward earth and humans from that. During the renaissance and the cultural periods after it, you would be increasingly inclined to start an argument first by saying, "Let's use scientific reasoning to figure out what is real and what humans can and should be and do."

But while our present-day arguments about being human may no longer start a priori with belief in God, they also no longer start a priori with the scientific method of reasoning. Philosophy has found room, often, for both logical, rational thinking and the possible existence of God. Since Kant, and because of him and others who came before him, philosophy in general respects both reason and respect for the life of feeling and intuitive knowledge.

In this regard--looking at both reason and one's inner life of feeling and intuition--philosophy has come full circle from the Golden Age of Greece. During that period several hundred years before the birth of Jesus, Greek philosophers also argued about the place of reason in human beings and the place of feelings and intuitions, much as philosophers do today.

 . However, they also are no longer purely rationalist or scientific arguments about how belief in God is a part of reason and logic. The world of philosophy and science has arrived instead, in the last century or two, at a method of arguing about God that encompasses use of reason, but also includes respect for the limitations of reason and use of feeling and intuitive knowledge. Most arguments about God's existence now discuss whether there are feelings, intuitions, and other senses beyond reason that help prove or disprove whether God is real. In many ways, we are, philosophically, back to 2500 years ago when the Greek philosophers were having similar arguments.

*Image in Chapter Title: Portrait of French philosopher Renee Descartes after Frans Hals: https://en.wikipedia.org/wiki/Ren%C3%A9_Descartes. Retrieved 17 Mar. 2020.

Most recent revision of text: 19 Mar. 2020



Richard Jewell

Contact Richard.

Public Web Addresses: www.ExperiencingTheHumanities.org www.CollegeHumanities.org, and www.OnlineHumanities.org
Natural URL:
Text copyright: 1987-2021 by Richard Jewell. You may use this text as a free online website without first receiving permission. However, printed copies may not be sold or distributed without obtaining permission. A MERLOT and Creative Commons OER Text
Photo and picture copyrights
: You may use all photos and pictures here as part of this free online website as described in "Text copyright" above. Most may be reprinted for nonprofit use. However, some are copyrighted, used here by permission, and may require permission for use beyond this website: for such reuse, see the credit line for the image in question.
Return to "Table of Contents."