Philosophy is a study that seeks answers to enduring questions about existence and reality. It tries to discover the nature of truth and knowledge and to find what is of basic value and importance in life. It also examines the relationships between humanity and nature and between the individual and society. Philosophy arises out of wonder, curiosity, and the desire to know and understand. Philosophy is thus a form of inquiry—a process of analysis, criticism, interpretation, reflection, and speculation.
The term philosophy cannot be defined precisely because the subject is so complex and so controversial. Different philosophers have different views of the nature, methods, and range of philosophy. The term philosophy itself comes from the Greek philosophia, which means love of wisdom. In that sense, wisdom is the active use of intelligence, not something passive that a person simply possesses.
Philosophy always has existed where people have sought wisdom by discussing better and worse ways of living. As ancient philosophy developed, logical reasoning became important in China, Greece, India, and Persia. Such reasoning often was connected with mathematics and with systematic (orderly) theorizing about the nature of observable things.
The first clearly recognizable Western philosophers lived in the ancient Greek world in the early 500’s B.C. They tried to discover the basic makeup of things and the nature of the world and reality. For answers to questions about such subjects, people largely had relied on magic, poetic wisdom literature, religion, superstition, and tradition. But the Greek philosophers considered such sources to be unreliable. They looked instead for sources of knowledge that were more systematic and which could be better justified. So they sought answers by thinking and by studying nature and geometry. They gave reasons and arguments for their views.
Philosophy also has had a long history in some non-Western cultures, especially in China and India. But until about 200 years ago, there was little interchange between Eastern and Western philosophies, chiefly because of difficulties of travel and communication. As a result, Western philosophy generally developed independently of Eastern philosophy. This article deals mainly with Western philosophy. For more information on Eastern philosophy, see the World Book articles on such Eastern traditions as Buddhism; Confucianism; Hinduism; and Taoism.
The importance of philosophy
Philosophic thought is an inescapable part of human existence. Almost everyone has been puzzled from time to time by such essentially philosophic questions as “What does life mean?” “Did I exist before I was born?” “What is the difference between right and wrong, and how can I know it?” “Is there life after death?” and “Where and how did the universe and life begin?” Most people also have some kind of philosophy in the sense of a personal outlook on life. Even a person who claims that considering philosophic questions is a waste of time is expressing his or her view of what is important, worthwhile, or valuable. A rejection of all philosophy is in itself a philosophy.
By studying philosophy, people can clarify what they believe and can be stimulated to think about ultimate questions in various subjects. A person can study philosophers of the past to discover why they thought as they did and what value their thoughts may have in one’s own life. Some people simply enjoy reading the great philosophers, especially those who were also great writers.
Philosophy has had enormous influence on our everyday lives. The very language we speak uses classifications derived from philosophy. For example, the classifications of noun and verb, true and false, and fact and fiction involve the philosophic idea that there are differences between things and actions and between knowledge and beliefs. If we ask what the differences are, we are starting a philosophic inquiry.
Every institution of society is based on philosophic ideas, whether that institution is the law, government, religion, family, marriage, industry, business, or education. Philosophic differences have led to the overthrow of governments, drastic changes in laws, and the transformation of economic systems. Such changes have occurred because the people involved held certain beliefs about what is important, true, real, and significant and about how life should be ordered.
Systems of education follow a society’s philosophic ideas about what children should be taught and for what purposes. Democratic societies stress that people should learn to think and make choices for themselves. Undemocratic societies discourage such activities and want their citizens to surrender their own interests to those of the state. The values and skills taught by the educational system of a society reflect the society’s philosophic ideas of what is important.
The branches of philosophy
Philosophic inquiry can be made into any subject because philosophy deals with everything in the world and all of knowledge. But traditionally, and for purposes of study, philosophy is divided into five branches, each organized around certain distinctive questions. The branches are metaphysics, epistemology, logic, ethics and political philosophy, and aesthetics. In addition, the philosophy of language became so important during the 1900’s that it is often considered another branch of philosophy.
Metaphysics
is the study of the fundamental nature of reality and existence and of the essences of things. Metaphysics often is divided into two areas—ontology and cosmology. Ontology is the study of being. Ontology asks what is, and what we mean when we say that something is. Cosmology is the study of the physical universe, sometimes called the cosmos, taken as a whole. Cosmology is also the name of the branch of science that studies the organization, history, and future of the universe.
Metaphysics deals with such questions as “What are the most basic components of reality?” “What is the distinction between appearance and reality?” “What are the most general principles and concepts by which our experiences can be interpreted and understood?” and “Do we possess free will, or are our actions determined by causes that we cannot control?”
Philosophers have developed a number of theories in metaphysics. These theories include materialism, idealism, mechanism, and teleology. Materialism maintains that only matter has real existence and that the activity of matter produces feelings, thoughts, and other mental phenomena. Idealism states that every material thing is an idea or a form of an idea. In idealism, mental phenomena are what is fundamentally important and real. Mechanism maintains that all happenings result from purely mechanical forces, not from purpose, and that it makes no sense to speak of the universe as having a purpose. In contrast, teleology states that the universe and everything in it exists and occurs for some purpose. See Idealism; Materialism; Mechanist philosophy; Metaphysics.
Epistemology
aims to determine the nature, basis, and extent of knowledge. It explores the various ways of knowing, the nature of truth, and the relationships between knowledge and belief. Epistemology asks such questions as “What are the features of genuine knowledge as distinct from what appears to be knowledge?” “What is truth, and how can we know what is true and what is false?” and “Are there different kinds of knowledge, with different grounds and characteristics?”
Philosophers often distinguish between two kinds of knowledge, a priori and a posteriori (also called empirical). We justify a priori knowledge by thinking, without independent appeal to experience. For example, we know that there are 60 seconds in a minute by learning the meanings of the terms. In the same way, we know that there are 60 minutes in an hour. From these facts, we can deduce that there are 3,600 seconds in an hour. We arrive at this conclusion by the operation of thought alone. We acquire a posteriori knowledge from observation and experience. For example, we know from observation how many keys are on a computer keyboard and from experience which key will type what letter.
The nature of truth has baffled people since ancient times, partly because people often use the term true for ideas they find congenial and want to believe, and also because people often disagree about which ideas are true. Philosophers have attempted to define criteria for distinguishing between truth and error. But they disagree about what truth means and how to arrive at true ideas. The correspondence theory holds that an idea is true if it corresponds to the facts or reality. The pragmatic theory maintains that an idea is true if it works or settles the problem it deals with. The coherence theory states that truth is a matter of degree and that an idea is true to the extent to which it coheres (fits together) with other ideas that one holds. Relativism says that what is true can vary, depending on the time, place, person, language, or culture. Skepticism claims that knowledge is impossible to attain and that truth is unknowable.
Logic
is the study of the principles and methods of reasoning. It explores how we distinguish between good (sound) reasoning and bad (unsound) reasoning. An instance of reasoning is called an argument or an inference. An argument consists of a set of statements called premises together with a statement called the conclusion, which is supposed to be supported by or derived from the premises. A good argument provides support for its conclusion, and a bad argument does not. Two basic types of reasoning are called deductive and inductive.
A good deductive argument is said to be valid. The argument’s conclusion necessarily follows from its premises in the sense that if the premises are granted to be true, the conclusion also must be true. A deductive argument whose conclusion does not follow necessarily from the premises is said to be invalid. The argument “All human beings are mortal, all Greeks are human beings, therefore all Greeks are mortal” is a valid deductive argument. But the argument “All human beings are mortal, all Greeks are mortal, therefore all Greeks are human beings” is invalid, even though the conclusion is true. On that line of reasoning, one could argue that all dogs, which are also mortal, are human beings.
Deductive reasoning is used to explore the necessary consequences of certain assumptions. Inductive reasoning is used to establish matters of fact and the laws of nature and does not aim at being deductively valid. One who reasons that all squirrels like nuts, on the basis that all squirrels so far observed like nuts, is reasoning inductively. The conclusion could be false, even though the premise is true. Nevertheless, the premise provides considerable support for the conclusion. See Deductive method; Inductive method; Logic.
Ethics and political philosophy
concern human conduct, character, and values. They study the nature of right and wrong and the distinction between good and evil. Ethics explores the nature of justice and of a just society, and also one’s obligations to oneself, to others, and to society (see Ethics). Political philosophy studies the nature of authority and government. It explores ways of organizing society so that its members cooperate to achieve certain purposes or values.
Ethics asks such questions as “What makes right actions right and wrong actions wrong?” “What is good and what is bad?” and “What are the proper values of life?” Problems arise in ethics because we often have difficulty knowing exactly what is the right thing to do. In many cases, our obligations conflict or are vague. In addition, people often disagree about whether a particular action or principle is morally right or wrong.
Relativism maintains that what is right or wrong depends on different points of view. What is right from one perspective may be wrong from another, so no basic standards exist for judging right or wrong. Objectivism claims that there are objective standards of right and wrong which can be discovered and which apply to everyone. Subjectivism states that moral standards are subjective matters of taste or opinion.
Two major traditions in modern political philosophy are Social Contract Theory and Utilitarianism. Social Contract Theory involves members of society agreeing with one another about the rules and principles that govern justice in certain social institutions. In Utilitarianism, the justice of actions and institutions are evaluated based on what will maximize happiness for the most people (see Utilitarianism).
Aesthetics
deals with the creation and principles of, and judgments about, art and beauty. It also studies the aesthetic experience—that is, our thoughts, feelings, and attitudes when we see, hear, or read something beautiful. Something beautiful may be a work of art, such as a painting, symphony, or poem, or a natural phenomenon, such as a sunset. Aesthetics also investigates the experience of engaging in such activities as acting, dancing, painting, and playing.
Aesthetics sometimes is identified with the philosophy of art, which deals with the nature of art and the aesthetic experience, the process of artistic creation, and the principles of criticism. But aesthetics has a wider application. It involves both works of art created by human beings and the beauty found in nature.
Aesthetics relates to ethics and political philosophy when we ask questions about what role art and beauty should play in society and in the life of the individual. Such questions include “How can people’s taste in the arts be improved?” “How should the arts be taught in the schools?” and “Do governments have the right to restrict artistic expression?” See Aesthetics.
The philosophy of language
Some philosophers claim that all philosophic questions arise from linguistic problems. Others claim that all philosophic questions are really questions about language. One key question is “What is language?” But there are also questions about the relationships between language and thought and between language and the world, as well as questions about the nature of meaning and definition.
Philosophers have asked whether there can be a logically perfect language that would reflect the essential characteristics of the world. This question raises more questions about the adequacy of ordinary language as a philosophic tool.
Philosophy and other fields
One peculiarity of philosophy is that the question “What is philosophy?” is itself a question of philosophy. But the question “What is art?” is not a question of art. The question is philosophic. The same is true of such questions as “What is history?” and “What is law?” Each is a question of philosophy. Such questions are basic to the philosophy of education, the philosophy of history, the philosophy of law, and other “philosophy of” fields. Each of these fields attempts to determine the foundations, fundamental categories, and methods of a particular institution or area of study. A strong relationship therefore exists between philosophy and other fields of human activity. This relationship can be seen by examining two fields: (1) philosophy and science and (2) philosophy and religion.
Philosophy and science.
Science studies natural phenomena and the phenomena of society. When science reflects on itself, it examines a number of philosophic questions. These questions include “What is science?” “What is the scientific method?” “Does scientific truth provide us with the truth about the universe and reality?” “What is the value of science?” and “Are the results of science biased, or democratic and objective?” Such questions are central to the philosophy of science.
Philosophy has given birth to several major fields of scientific study. Until the 1700’s, no distinction was made between science and philosophy. For example, physics was called natural philosophy. Psychology was part of what was called moral philosophy. In the early 1800’s, sociology and linguistics separated from philosophy and became distinct areas of study.
Logic always has been considered a branch of philosophy. Logic also has developed as a branch of mathematics, which is a basic science. As philosophers, logicians study the structure of formal arguments and whether or not they make sense. As mathematicians, logicians study the relations among and between objects and languages, the structure of proof, and the theory of computation (calculation).
Philosophy and science differ in many respects. For example, science has attained definite and tested knowledge of many matters and has resolved disagreement about those matters. Philosophy has not done so. As a result, controversy always has been characteristic of philosophy. Science and philosophy do share one significant goal. Both seek to discover the truth—to answer questions, solve problems, and satisfy curiosity. In the process of doing so, both science and philosophy generate further questions and problems, and each solution brings with it even more questions and problems.
Philosophy and religion.
Historically, philosophy originated in religious questions. These questions concerned the nature and purpose of life and death and the relationship of humanity to superhuman powers or a divine creator. Every society has some form of religion. Most people acquire their religion from their society as they acquire their language. Philosophy inquires into the essence of things, and inquiry into the essence of religion is a philosophic inquiry.
Religious ideas generated some of the earliest philosophic speculations about the nature of life and the universe. The speculations often centered on the idea of a supernatural or superpowerful being who created the universe and who governs it according to unchangeable laws and gives it purpose. Western philosophic tradition has paid much attention to the possibility of demonstrating the existence of God.
The chief goal of some philosophers is not understanding and knowledge. Instead, they try to help people endure the anxiety, pain, and suffering of earthly existence. Such philosophers attempt to make philosophic reflection on the nature and purpose of life perform the function of religion.
Eastern philosophy
Two important traditions in Eastern philosophy are the Chinese and Indian traditions. Both are basically religious and ethical in origin and character. They are removed from any interest in science.
Chinese philosophy traditionally has been humanistic, practical, and social in its aims. It developed as a means of improving society and politics. It typically called for people to participate in the life of the state to improve worldly conditions.
Chinese philosophy as we know it started in the 500’s B.C. with the philosopher Confucius. His philosophy, called Confucianism, was the official philosophy of China for centuries, though it was reinterpreted by different generations. Confucianism aimed to help people live better and more rewarding lives through discipline and instruction in the proper goals of life. Candidates for government positions had to pass examinations on Confucian thought, and Confucianism formed the basis for government decisions. See Confucianism.
Other philosophic traditions from China have included Taoism, Mohism, and Realism (see Taoism). Beginning in the 1100’s, a movement known as Neo-Confucianism incorporated elements of all these traditions.
Philosophy in India traditionally has been mystical rather than political. A reliance on sacred texts called the Vedas has dominated Indian philosophy. The Vedas are viewed as inspired and true, yet subject to interpretation and analysis. Much of Indian philosophy has emphasized withdrawal from worldly life into the life of the spirit. It also has stressed the distinction between appearance and reality.
We do not know exactly when Indian philosophy began. In India, philosophic thought was closely associated with religion. Philosophic commentaries on sacred texts emerged during the 500’s B.C. The Indian word for these commentaries is darshana, which means vision or seeing. It corresponds to what the ancient Greeks called philosophia.
The main aim of Indian philosophy was freedom from the suffering and tension caused by the body and the senses and by attachment to worldly things. The main philosophies developed in India were Hinduism and Buddhism, which were also religions. However, some Indian philosophers developed a complex system of logic and studied epistemology. Some ideas from Indian philosophy have been influential in the West. One such idea is reincarnation, the belief that the human soul is reborn successively in new bodies. See Buddhism; Hinduism.
The history of Western philosophy
The history of Western philosophy commonly is divided into three periods—ancient, medieval, and modern. The period of ancient philosophy extended from about 600 B.C. to about the A.D. 400’s. Medieval philosophy lasted from the 400’s to the 1600’s. Modern philosophy covers the period from the 1600’s to the present. It is important to note that since the late 1700’s, Eastern philosophies have influenced some important Western philosophers, and vice versa.
Ancient philosophy
in the West developed in Greece during the early 500’s B.C. The greatest philosophers of the ancient world were three Greeks of the 400’s and 300’s B.C.—Socrates, Plato, and Aristotle. Their philosophy influenced all later Western culture. Modern ideas in the fields of ethics, logic, metaphysics, and science originated from their thought. A number of distinctive schools of philosophy also flourished in ancient Greece.
The pre-Socratics
were the first Greek philosophers. Their name comes from the fact that most of them lived before the birth of Socrates in about 470 B.C. The pre-Socratic philosophers were interested mainly in the nature and source of the universe and the nature of reality. They wanted to identify the fundamental substance that they thought underlay all phenomena, and in terms of which all phenomena could be explained. The pre-Socratics also became interested in logic.
Unlike most other people of their time, the pre-Socratic philosophers did not believe that gods or supernatural forces caused natural events. Instead, they sought a scientific explanation for natural phenomena. They saw the universe as a set of connected and unified phenomena for which thought could find an explanation. They gave many different and conflicting answers to basic philosophic questions. However, the importance of the pre-Socratics lies not in the truth of their answers but in the fact that they examined the questions in the first place. Their ideas provided a tradition for all later philosophers. See Pre-Socratic philosophy.
Socrates
constantly was engaged in philosophic discussion, but he left no writings. Modern knowledge of his ideas and methods comes mainly from dialogues written by his pupil Plato. In most of the dialogues, Socrates appears as the main character, who leads and develops the process of inquiry.
Socrates lived in Athens and taught in the city’s streets, market place, and gymnasiums. He taught by a question-and-answer method. Socrates tried to get a definition or precise view of some abstract idea, such as knowledge, virtue, justice, or wisdom. He would use close, sharp questioning, constantly asking “What do you mean?” and “How do you know?” This procedure, called the Socratic method, became the model for philosophic methods that emphasize debate and discussion.
Socrates wanted to replace vague opinions with clear ideas. He often questioned important Athenians and exposed their empty claims to knowledge and wisdom. This practice made him many enemies, and he was sentenced to death as a danger to the state. He thus became a symbol of the philosopher who pursued an argument wherever it led to arrive at the truth, no matter what the cost. See Socrates.
Plato
believed that we cannot gain knowledge of things through our senses because the objects of sense perception are fleeting and constantly changing. Plato stated that we can have genuine knowledge only of changeless things, such as truth, beauty, and goodness, which are known by the mind. He called such things ideas or forms.
Plato taught that only ideas are real and that all other things only reflect ideas. This view became known as Idealism. According to Plato, the most important idea is the idea of good. Knowledge of good is the chief object of all inquiry. Plato considered the best life to be one of contemplation of eternal truths, such as those of geometry. He also believed that people who have attained this state must use their skills and knowledge to serve humanity. Plato believed that the soul is immortal and that only the body perishes at death. His ideas contributed to later Christian ideas about the body, the soul, and eternal things. See Plato.
Aristotle,
Plato’s greatest pupil, wrote about almost every known subject of his day. He invented the idea of a science and of separate sciences, each having distinct principles and dealing with different subject matter. He wrote on such topics as anatomy, astronomy, biology, physics, physiology, and psychology. Aristotle also investigated what he called “first philosophy,” later known as metaphysics.
Aristotle created the earliest philosophic system. In his philosophy, all branches of inquiry and knowledge are parts of some overall system and connected by the same concepts and principles. Aristotle believed that all things in nature have some purpose. According to his philosophy, the purpose of each thing determines its nature, and each thing seeks to fulfill its nature by carrying out its purpose.
Aristotle’s basic method of inquiry consisted of starting from what we know or think we know and then asking how, what, and why. In his metaphysics, he developed the idea of a first cause as the ultimate explanation of existence. The first cause itself was not caused by anything. Christian theologians later adopted this idea as a basic argument for the existence of God.
Aristotle taught that everyone aims at some good. He said that happiness does not lie in pleasure but in virtuous activity. By virtuous activity, he meant acting according to a mean between extremes. For example, courage is the mean between the extremes of cowardice and foolhardiness. Aristotle believed that the highest happiness of all is the contemplative use of the mind. See Aristotle.
Stoic philosophy and Epicureanism
were the two main schools of Greek philosophy that emerged after the death of Aristotle in 322 B.C. Both schools taught that the purpose of knowing is to enable a person to lead the best and most contented life.
Zeno of Citium founded Stoic philosophy. Zeno taught that people should spend their lives trying to cultivate virtue, the greatest good. The Stoics believed in strict determinism—that is, the idea that all things are fated to be. Therefore, they said, a wise and virtuous person accepts and makes the best of what cannot be changed. Stoicism spread to Rome. The chief Roman Stoics included the statesman Marcus Tullius Cicero, Emperor Marcus Aurelius, and the teacher Epictetus. See Stoic philosophy.
Epicurus founded Epicureanism. Epicurus based his philosophy on hedonism—that is, the idea that the only good in life is pleasure. However, Epicurus taught that not all pleasures are good. The only good pleasures are calm and moderate ones, because extreme pleasures could lead to pain. Epicurus said that the highest pleasures are physical health and peace of mind, two kinds of freedom from pain. See Epicurus.
Skepticism
was a school of philosophy founded by Pyrrho of Elis about the same time that Stoicism and Epicureanism flourished. Pyrrho taught that we can know nothing. Our senses deceive us and provide no accurate knowledge of the way things are. Thus, all claims to knowledge are false. Because we can know nothing, we should treat all things with indifference and make no judgments. See Skepticism.
Neoplatonism
was a revived version of some of Plato’s ideas as adapted by Plotinus, a philosopher who may have been born in Egypt in the A.D. 200’s. Neoplatonism tried to guide the individual toward a blessed state of oneness (unity) with God. Plotinus believed that the human soul yearns for reunion with God and that it can achieve this reunion only in mystical experience. Neoplatonism provided the bridge between Greek philosophy and early Christian philosophy. It inspired the idea that only faith and God’s influence, and not reason, can lead to important truths. See Neoplatonism.
Medieval philosophy.
During the Middle Ages, Western philosophy developed more as a part of Christian theology than as an independent branch of inquiry. Theology means the study of God, or a system of religious beliefs. The philosophy of Greece and Rome survived only in its influence on religious thought.
Saint Augustine << AW guh `steen` or aw GUHS tihn >> was the greatest philosopher of the early Middle Ages. Augustine wrote The City of God in the early 400’s. In this book, he interpreted human history as a conflict between faithful Christians living in the city of God and non-Christians and heretics (people with beliefs rejected by the church) living in the city of the world. Augustine wrote that the people in the city of God will gain eternal salvation, but the people in the city of the world will receive eternal punishment. The book weakened the belief in the religion of ancient Rome and helped further the spread of Christianity. See Augustine, Saint.
A system of thought called Scholasticism dominated medieval philosophy from about the 1100’s to the 1400’s. The name Scholasticism refers to the method of philosophic investigation used by philosophy and theology instructors at the universities developing in western Europe at that time. The instructors were called Scholastics. The Scholastic method consisted of the precise analysis of concepts, with subtle distinctions between different senses of these concepts. The Scholastics used deductive reasoning based on principles established by their method to solve problems.
The translation of Aristotle’s works into Latin, the language of the medieval Christian church, generated Scholasticism. Medieval thinkers faced the challenge of reconciling Aristotle’s work with the Bible and Christian doctrine (official teaching). The most famous Scholastic was Saint Thomas Aquinas. His philosophy combined Aristotle’s thought with theology. It eventually became the official philosophy of the Roman Catholic Church.
The Scholastics’ contributions to philosophy included major development of the philosophy of language. The Scholastics studied how features of language can affect our understanding of the world. They also stressed the importance of logic to philosophic inquiry. See Scholasticism.
Modern philosophy.
A great cultural movement in Europe called the Renaissance overlapped the end of the Middle Ages and formed a transition between medieval and modern philosophy. The Renaissance began in Italy and lasted from about 1300 to about 1600. It was a time of intellectual reawakening that stemmed from the rediscovery of ancient Greek and Roman culture.
During the Renaissance, major advances occurred in such sciences as astronomy, mathematics, and physics. Scholars called humanists stressed the importance of human beings and the study of classical literature as a guide to understanding life (see Humanism). Emphasis on science and on humanism led to changes in the aims and techniques of philosophic inquiry. Scholasticism declined, and philosophy was freed of its ties to medieval theology.
Francis Bacon of England was one of the earliest philosophers to support the scientific method, an orderly method used in scientific research. Most historians consider Bacon and René Descartes of France to be the founders of modern philosophy. Bacon wrote two influential works, The Advancement of Learning (1605) and Novum Organum (1620). He stated that knowledge was power and that knowledge could be obtained only by the inductive method of investigation. Bacon imagined a new world of culture and leisure that could be gained by inquiry into the laws and processes of nature. In describing this world, he anticipated the effects of advances in engineering, science, and technology. See Bacon, Francis.
Rationalism
was a philosophic outlook that arose in the 1600’s. The basic idea of Rationalism is that reason is superior to experience as a source of knowledge and that the validity of sense perception must be proved from more certain principles. The Rationalists tried to determine the nature of the world and of reality by deduction from premises established as a priori. They stressed the importance of mathematical procedures. The leading Rationalists were René Descartes, Baruch Spinoza, and Gottfried Wilhelm Leibniz. See Rationalism.
Descartes was a mathematician as well as a philosopher. Descartes’s basic philosophic idea was to establish a secure foundation for the sciences, as he had established a secure foundation for mathematics. Descartes was much concerned with the foundations of knowledge. His work began philosophy’s persistent consideration of epistemological problems. Descartes was a mechanist—that is, he regarded all physical phenomena as connected mechanically by laws of cause and effect. Descartes also believed that the soul, or mind, and our ideas are distinct from our physical bodies. His philosophy generated the problem of how mind and matter are related. See Descartes, Rene.
Spinoza modeled his system of philosophy on geometry. He attempted to derive philosophic conclusions from a few central axioms (supposedly self-evident truths) and definitions. Spinoza did not view God as a superhuman being who created the universe. He claimed that God and nature were the same, and that the universe and the mind were expressions of God. Spinoza was also a mechanist. He regarded everything in the universe as rational and, thus, determined. Spinoza’s main aim was ethical. He wanted to show how people could be free and lead reasonable and satisfying lives in a deterministic world. See Spinoza, Baruch.
Leibniz believed that the actual world is only one of many possible worlds. In an effort to justify the ways of God to humanity, Leibniz tried to show how the actual world is the best of all possible worlds. Thus, he attempted to solve the problem of how a perfect and all-powerful God could have created a world filled with so much suffering and evil. See Leibniz, Gottfried Wilhelm.
Leibniz and the English scientist Sir Isaac Newton independently developed calculus, a branch of mathematics that deals with the notion of the infinite. Leibniz’s work in mathematics anticipated the development of symbolic logic—the use of mathematical symbols and operations to solve problems in logic.
Empiricism
emphasizes the importance of experience and sense perception as the source of knowledge. The first great Empiricist was John Locke of England in the 1600’s. George Berkeley of Ireland and David Hume of Scotland further developed Empiricism in the 1700’s. See Empiricism.
Locke tried to determine the origin, extent, and certainty of human knowledge in An Essay Concerning Human Understanding (1690). Locke argued that there are no innate ideas—that is, ideas with which people are born. He believed that when a person is born, the mind is like a blank piece of paper. Experience is therefore the source of all ideas and knowledge. See Locke, John.
George Berkeley dealt with the issue of existence. According to Berkeley, to exist is to perceive or be perceived. The only things that exist are “active spirits” that perceive and “passive ideas” that are perceived.
Berkeley rejected the belief that objects are made of matter. He argued instead that objects are ideas in a mind. They exist because a mind perceives them. For example, an apple exists because a mind perceives such qualities as its color, taste, texture, and smell. The theory that objects exist only in the mind is called Idealism.
Objects can exist when human beings are not perceiving them, because the universally present mind of God perceives them. Berkeley also maintained that the ideas in human minds come from God. See Berkeley, George.
Hume extended the theories of Locke and Berkeley to a consistent skepticism about almost everything. Hume maintained that everything in the mind consists of impressions and ideas, and that every idea can be traced to and tested by some earlier impression. For an idea to have meaning, we must be able to determine from what impression we derived it. An apparent idea that cannot be traced to an impression must be meaningless.
Hume also raised the question of how we can know that the future will be like the past and that the laws of nature will continue to operate as they have. He claimed that we can only know that events have followed certain patterns in the past. We cannot be certain that events will continue to follow those patterns. Hume influenced the foundation of modern psychology. See Hume, David.
The Enlightenment
was a period of great intellectual activity that began in the 1600’s and lasted until the late 1700’s (see Enlightenment). This period is also called the Age of Reason. Philosophers of the Enlightenment stressed the use of reason, as opposed to a reliance on religious scriptures and other authorities. They believed that reason provided the means of attaining the truth about the world and of ordering human society to assure human well-being. Leading Enlightenment philosophers included Berkeley, Descartes, Hume, and Locke. They also included Denis Diderot, Jean-Jacques Rousseau, Voltaire, and other members of a group of French philosophers called the Philosophes (see Philosophes).
Locke’s philosophic ideas were characteristic of the Enlightenment. Locke sought to determine the limits of human understanding and to discover what can be known within those limits that will serve as a guide to life and conduct. He tried to show that people should live by the principles of liberty, natural rights, and toleration. His Two Treatises of Government (1690) provided the philosophic basis for the American and the French revolutions in the late 1700’s.
The philosophy of Immanuel Kant,
a great German philosopher of the late 1700’s, became the foundation for nearly all later developments in philosophy. Kant’s philosophy is called Critical Philosophy or Transcendental Philosophy. The Skeptical philosophy of Hume stimulated Kant to try to bring about a synthesis of Rationalism and Empiricism. In his Critique of Pure Reason (1781), Kant tried to provide a critical account of the powers and limits of human reason, in order to determine what is knowable and what is unknowable. Kant concluded that reason can provide knowledge only of things as they appear to us, never of things as they are in themselves.
Kant believed that the mind not only records impressions collected by the senses, but that it plays an active role in knowing. The mind does this by organizing our past experiences into basic categories or concepts of understanding that are independent of the experiences themselves. These categories enable us to make sense of our experiences and to have knowledge, but only of things that can or might be experienced with the senses.
Kant criticized the traditional arguments for the existence of God. He argued that they are all in error because they make claims that go beyond the possibility of experience, and thus beyond the powers of human reason. In his Critique of Practical Reason (1788), Kant argued that practical reason (reason applied to practice) can show us how we ought to act. It also provides a practical reason for believing in God, though not a proof that God exists. See Kant, Immanuel.
Philosophy in the 1800’s.
Kant’s philosophy stimulated various systems of thought in the 1800’s, such as those of G. W. F. Hegel and Karl Marx of Germany. Hegel developed a theory of historical change called dialectic, in which the conflict of opposites results in the creation of a new unity and then its opposite. Marx transformed Hegel’s theory into dialectical materialism. Marx believed that only material things are real. He stated that all ideas are built on an economic base. He believed that the dialectic of conflict between capitalists and industrial workers would lead to the establishment of Communism, which he called socialism. See Hegel, G. W. F.; Marx, Karl.
Kant’s work also stimulated the development of a literary movement called Romanticism and a philosophy called Transcendentalism. Philosophers and writers of these movements tried to understand the place of human life within nature. They included the German writer Johann Wolfgang von Goethe, the German philosopher Friedrich Wilhelm Joseph von Schelling, and the American writers Henry David Thoreau and Ralph Waldo Emerson. See Romanticism; Transcendentalism.
Friedrich Nietzsche was a German philosopher and an atheist. In his book Thus Spake Zarathustra (1883-1885), Nietzsche proclaimed that “God is dead.” Nietzsche meant that the idea of God had lost the power to motivate and discipline large masses of people. He believed that people would have to look to some other idea to guide their lives.
Nietzsche predicted the evolution of the superman, who would be beyond the weakness of human beings and beyond merely human appeals to morality. He regarded such appeals as appeals to weakness, not strength. Nietzsche thought that all behavior is based on the will to power—the desire of people to control their own passions and other people. The superman would develop a new kind of excellence through his capacity to realize the will to power through strength, rather than weakness. See Nietzsche, Friedrich.
The dominant philosophy in England during the 1800’s was Utilitarianism, developed by Jeremy Bentham and John Stuart Mill. The Utilitarians maintained that the greatest happiness for the greatest number of people is the test of right and wrong. They argued that all existing social institutions, especially law and government, must be transformed to satisfy the test of greatest happiness. In The Subjection of Women (1869), Mill wrote that the legal subordination of women to men ought to be replaced by “a principle of perfect equality.” This idea was revolutionary in Mill’s time, although such women as the British author Mary Wollstonecraft had argued earlier that women should have equality with men. See Bentham, Jeremy; Mill, John Stuart.
Philosophy in the 1900’s.
Five main movements dominated philosophy in the 1900’s. Two of these movements—Phenomenology and Existentialism—had their greatest influence on the mainland of western Europe. The other three movements—Pragmatism, Logical Positivism, and Analytic Philosophy—were influential chiefly in the United States and the United Kingdom. All five movements sought to place knowledge on a firm foundation and to make philosophy scientific or practical. Philosophers around the world continue to work within most of these movements. Feminist philosophy also began developing in the mid-1900’s, as philosophers focused more on such subjects as health and poverty, and on the practical problems of human development.
The German philosopher Edmund Husserl developed Phenomenology. Husserl thought the task of philosophy was to describe phenomena (the objects of experience) accurately and independently of all assumptions derived from science. He thought this activity would provide philosophic knowledge of reality. See Phenomenology.
Existentialism became influential in the mid-1900’s. World War II (1939-1945) gave rise to widespread feelings of despair and separation from the established order. These feelings led to the idea that people must create their own values in a world lacking traditional values. Existentialists see life as a series of decisions that must be made without knowing for certain what the correct choices are. There are no objective standards to which a person can turn for answers, because different standards supply conflicting advice. Therefore, human choice is subjective (dependent on the mind of the individual). The most famous Existentialist philosophers include the French author Jean-Paul Sartre and the German philosopher Martin Heidegger, an assistant of Edmund Husserl. See Existentialism.
Pragmatism maintains that knowledge is subordinate to action. The meaning and truth of an idea is determined by that idea’s relation to practice. The British naturalist Charles Darwin’s theories of evolution strongly affected the Pragmatists, who sought to understand how values could make sense in a world of chance. Prominent Pragmatists of the 1900’s included the Americans John Dewey, William James, and Charles Sanders Peirce. See Pragmatism.
Logical Positivism developed in Vienna, Austria, in the 1920’s. The movement generally is regarded as having ended in the 1950’s. Logical Positivists thought philosophy should analyze the logic of the language of science. They regarded science as the only source of knowledge and claimed that metaphysics was meaningless. They based this claim on the principle of verifiability, by which a statement is meaningful only if it can be verified by sense experience.
Logical Positivists also believed in emotivism. According to emotivism, statements about morality are not expressions of facts, but rather of feelings.
Logical Positivism originated in the ideas of Hume and Kant. It was stimulated by the work of the German mathematician Gottlob Frege; the British philosopher Bertrand Russell, who developed formalized languages for logic; and the Austrian-born British philosopher Ludwig Wittgenstein. The theories of relativity set forth by the German-born American physicist Albert Einstein also influenced the development of Logical Positivism. For Logical Positivists, relativity meant that we can never verify that absolute space and absolute time exist. See Positivism.
Analytic Philosophy generally tries to solve philosophic problems through the logical analysis of language or concepts. Such analysis breaks down concepts into their basic elements. Some versions of this philosophy attempt to show that traditional philosophic problems dissolve (disappear) upon proper analysis of the terms in which they are expressed. Other versions of Analytic Philosophy seek to throw light on, not dissolve, traditional philosophic problems. The most influential philosophers practicing Analytic Philosophy have been Bertrand Russell and Ludwig Wittgenstein. See Russell, Bertrand; Wittgenstein, Ludwig.
Wittgenstein made logic and the structure of language central to philosophy. He urged that philosophers should investigate language in great detail. He developed the notion of a “language-game,” a simplified model of language that has rules and moves, as a board game has. He used this model to compare different uses of language and different ideas about human thought. Wittgenstein influenced many philosophers of language, as well as the British computer pioneer Alan Turing. He also influenced philosophers of religion who studied the rationality of religious belief.
