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 (1) metaphysics, (2) epistemology, (3) logic, (4) ethics, and (5) aesthetics. In addition, the philosophy of language has become 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 is itself often divided into two areas–ontology and cosmology. Ontology is the study of being. Cosmology is the study of the physical universe, or 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 is real?” “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 over which we have no 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 feelings, thoughts, and other mental phenomena are produced by the activity of matter. 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 itself as having a purpose. Teleology, on the other hand, states that the universe and everything in it exists and occurs for some purpose.
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 empirical. We arrive at 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, and we arrive at this conclusion by the operation of thought alone. We acquire empirical knowledge from observation and experience. For example, we know from observation how many keys are on a typewriter and from experience which key will print what letter.
The nature of truth has baffled people since ancient times, partly because people so often use the term true for ideas they find congenial and want to believe, and also because people so 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. 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 (or sound) reasoning and bad (or 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–that is, the conclusion necessarily follows from the premises. 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.
Ethics concerns human conduct, character, and values. It studies 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.
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.
A view called relativism maintains that what is right or wrong depends on the particular culture concerned. What is right in one society may be wrong in another, this view argues, and so no basic standards exist by which a culture may be judged 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 all moral standards are subjective matters of taste or opinion.
Aesthetics deals with the creation and principles of art and beauty. It also studies 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 it may be a sunset or other natural phenomenon. In addition, aesthetics investigates the experience of engaging in such activities as painting, dancing, acting, and playing.
Aesthetics is sometimes identified with the philosophy of art, which deals with the nature of art, the process of artistic creation, the nature of the aesthetic experience, and the principles of criticism. But aesthetics has 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?”
The Philosophy of Language has become especially important in recent times. Some philosophers claim that all philosophic questions arise out of 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 of definition.
The question has been raised whether there can be a logically perfect language that would reflect in its categories the essential characteristics of the world. This question raises questions about the adequacy of ordinary language as a philosophic tool. All such questions belong to the philosophy of language, which has essential connections with other branches of philosophy.