Sociology is a branch of the social sciences that uses systematic methods of empirical investigation  and critical analysis to develop and refine a body of knowledge about human social structure and activity, sometimes with the goal of applying such knowledge to the pursuit of social welfare. Its subject matter ranges from the micro level of face-to-face interaction to the macro level of societies at large.
Sociology is a broad discipline in terms of both methodology and subject matter. Its traditional focuses have included social relations, social stratification, social interaction, culture and deviance, and its approaches have included both qualitative and quantitative research techniques. As much of what humans do fits under the category of social structure or social activity, sociology has gradually expanded its focus to such far-flung subjects as the study of economic activity, health disparities, and even the role of social activity in the creation of scientific knowledge. The range of social scientific methods has also been broadly expanded. The "cultural turn" of the 1970s and 1980s brought more humanistic interpretive approaches to the study of culture in sociology. Conversely, the same decades saw the rise of new mathematically rigorous approaches, such as social network analysis.
See main article: History of sociology.
Sociological reasoning is much older than the term “sociology.” Sociology, including economic, political, and cultural systems, has proto-sociological origins in the common stock of human knowledge and philosophy. Social analysis has been carried out by scholars and philosophers from at least as early as the time of Plato.
The word was later used in 1838 by the French thinker Auguste Comte. Comte had earlier used the term "social physics", but that term had subsequently been appropriated by others, notably Adolphe Quetelet. Comte hoped to unify history, psychology and economics. He believed that society's acquisition of knowledge passed through three basic stages: theological, metaphysical, and positive. Comte argued that if society could grasp the structure of this progress, it could prescribe suitable remedies for social ills. Comte has come to be viewed as the "Father of Sociology".
Sociology later evolved, as a scientific discipline, as an academic response to the challenges of modernity and modernization, such as industrialization and urbanization, that emerged in the early 19th century.
"Classical" theorists of sociology from the late 19th and early 20th centuries include Vilfredo Pareto, Karl Marx, Ludwig Gumplowicz, Ferdinand Tönnies, Émile Durkheim, Herbert Spencer, Georg Simmel, Max Weber, and George Herbert Mead. Like Comte, these figures did not consider themselves only "sociologists". Their works addressed religion, education, economics, law, psychology, ethics, philosophy and theology. Their theories have been applied in a variety of academic disciplines and beyond. Each key figure is typically associated with a particular theoretical perspective and orientation used to interpret and understand human behaviour.
Other significant figures include Raymond Aron, Jean Baudrillard, Zygmunt Bauman, Howard Becker, Daniel Bell, Peter Berger, Peter Blau, Herbert Blumer, Pierre Bourdieu, Dieter Claessens, Randall Collins, Charles Horton Cooley, Lewis A. Coser, Ralf Dahrendorf, W. E. B. Dubois, Norbert Elias, Gilberto Freyre, Michel Foucault, Herbert Gans, Harold Garfinkel, Anthony Giddens, Erving Goffman, George Homans, Thomas Luckmann, Karl Mannheim, Marcel Mauss, Robert K. Merton, Robert Michels, C. Wright Mills, Talcott Parsons, Gabriel Tarde, W. I. Thomas, Thorstein Veblen, and Immanuel Wallerstein.
The discipline was taught under its own name for the first time in 1890, at the University of Kansas, Lawrence. The course, whose title was Elements of Sociology, was first taught by Frank Blackmar. It is the oldest continuing sociology course in the United States. The Department of History and Sociology at the University of Kansas, the first fully fledged independent university in the United States, was established in 1891.  The department of sociology at the University of Chicago was established in 1892 by Albion W. Small, who, in 1895, founded the American Journal of Sociology.
The first European department of sociology was founded in 1895, at the University of Bordeaux by Émile Durkheim, founder of L'Année Sociologique (1896). The first sociology department to be established in the United Kingdom was at the London School of Economics and Political Science (home of the British Journal of Sociology) in 1904. In 1919, a sociology department was established in Germany at the Ludwig Maximilians University of Munich by Max Weber, and in 1920 in Poland by Florian Znaniecki.
International co-operation in sociology began in 1893, when René Worms founded the Institut International de Sociologie, which was later eclipsed by the much larger International Sociological Association (ISA), founded in 1949. In 1905, the American Sociological Association, the world's largest association of professional sociologists, was founded, and in 1909 the Deutsche Gesellschaft für Soziologie (German Society for Sociology) was founded by Ferdinand Tönnies and Max Weber, among others.
The methodological approach towards sociology by early theorists, led by Comte, was to treat it in much the same manner as natural science, applying much the same methods as those used in the natural sciences. The emphasis on empiricism and the scientific method sought to provide an incontestable foundation for any sociological claims or findings, and to distinguish sociology from less empirical fields such as philosophy. This methodological approach, called positivism, is based on the assumption that the only authentic knowledge is scientific knowledge, and that such knowledge can come only from positive affirmation of theories through strict scientific and quantitative methods.
Reactions against positivism began when German philosopher Georg Wilhelm Friedrich Hegel voiced opposition to both empiricism, which he rejected as uncritical, and determinism, which he viewed as overly mechanistic. Although Karl Marx's dialectical materialism - as Marx's colleague Friedrich Engels referred to his and Marx's methodology - contrasted sharply with Hegel's idealism, his methodology was Hegelian insofar as it rejected positivism in favour of critical analysis, which seeks to supplement the empirical acquisition of "facts" with the elimination of illusions. As critical theorists David Ashley and David Michael Orenstein observe, "Marx often pointed out that rational inquiry would be superfluous if the essence of things coincided directly with appearances"; Marx thus understood that appearances need to be critiqued, not simply documented.
Other philosophers, including Heinrich Rickert and even the empiricist Wilhelm Dilthey, questioned positivist and naturalist approaches to studying social life. Rickert and Dilthey argued that the natural world differs from the social world because of unique aspects of human society, such as meanings, symbols, rules, norms, and values, all of which inform human cultures. This view was further developed by Max Weber, who introduced the term antipositivism. According to this view, which is closely related to antinaturalism, sociological research should concentrate on human cultural values, symbols, and social processes viewed from a subjective perspective.
Weber was a hermeneuticist, more interested in interpreting subjective meaning than in charting objective action. Yet he also felt that sociology should be a "science", able to identify causal relationships - especially among ideal types, or hypothetical simplifications of complex social phenomena. As a nonpositivist, however, Weber recognized that the selection and construction of ideal types was itself a subjective process, and realized that, unlike the causal relationships sought in positivistic science, those found between ideal types are not "ahistorical, invariant, or generalizable." For example, Ashley and Orenstein point out that Weber, in his seminal work, The Protestant Ethic and the Spirit of Capitalism, did not intend to suggest that the spirit of capitalism could not flourish outside the Protestant ethic (it has) or that factors outside the Protestant ethic did not contribute to the spirit of capitalism in the West (they did). What mattered to Weber was that the relationship between the two factors helped to distinguish the character of Western Europe - and the meaning derived by the subjects in it - from the rest of the world.
Émile Durkheim was a major proponent of empirical sociological research, both qualitative and quantitative. For example, he used ethnographic data to theorize about the social origins of religion, and compiled statistical information in order to understand the social roots of suicide. Yet his empirical bent may be overstated, perhaps as a result of the co-opting of his theories by the American positivist Talcott Parsons. Durkheim gathered data, not for data's sake, but in order to understand and promote social evolution and reform. Additionally, therefore, the original spirit of Durkheim's work may have become distorted by a growing disjuncture between institutionalized academia on the one hand, and the agitation and dynamics of reform and progress on the other.
In the early 20th century, sociology expanded in the United States of America, including developments in both macrosociology, concerned with the evolution of societies, and microsociology, concerned with everyday human social interactions. Based on the pragmatic social psychology of George Herbert Mead, Herbert Blumer and, later, the Chicago school), sociologists developed symbolic interactionism.
In Europe, in the Interwar period, sociology generally was both attacked by increasingly totalitarian governments and rejected by conservative universities. At the same time, originally in Austria and later in the U.S., Alfred Schütz developed social phenomenology, which would later inform social constructionism. Also, members of the Frankfurt school, most of whom moved to the U.S. to escape Nazi persecution, developed critical theory, integrating critical, idealistic and historical materialistic elements of the dialectical philosophies of Hegel and Marx with the insights of Freud, Max Weber - in theory, if not always in name - and others. In the 1930s in the U.S., Talcott Parsons developed structural-functional theory which integrated the study of social order and "objective" aspects of macro and micro structural factors.
Since World War II, sociology has been revived in Europe, although during the Stalin and Mao eras it was suppressed in the communist countries. In the mid-20th century, there was a general - but not universal - trend for U.S.-American sociology to be more scientific in nature, due partly to the prominence at that time of structural functionalism. Sociologists developed new types of quantitative and qualitative research methods. In the second half of the 20th century, sociological research has been increasingly employed as a tool by governments and businesses. Parallel with the rise of various social movements in the 1960s, theories emphasizing social struggle, including conflict theory, which sought to counter structural functionalism, and neomarxist theories, began to receive more attention.
The positivist tradition continues to be highly influential in sociology, especially in the United States. The discipline's two leading journals, American Journal of Sociology and American Sociological Review, primarily publish research in the positivist tradition. Social network analysis is an example of a new paradigm in this tradition. The influence of social network analysis is pervasive in many sociological sub fields such as economic sociology (see the work of J. Clyde Mitchell, Harrison White, or Mark Granovetter, for example), organizational behavior, historical sociology, political sociology, or the sociology of education. There is also a minor revival of a more independent, empirical sociology in the spirit of C. Wright Mills, and his studies of the Power Elite in the United States of America, according to Stanley Aronowitz.
Throughout the development of sociology, controversies have raged about how to emphasize or integrate concerns with subjectivity, objectivity, intersubjectivity and practicality in theory and research. The extent to which sociology may be characterized as a "science" has remained an area of considerable debate, which has addressed basic ontological and epistemological philosophical questions. One outcome of such disputes has been the ongoing formation of multidimensional theories of society, such as the continuing development of various types of critical theory. Another outcome has been the formation of public sociology, which emphasizes the usefulness of sociological analysis to various social groups.
Sociology as a discipline never had well-defined boundaries. Although throughout the early 19th century it was primarily concerned with the social organization of complex industrial societies, it has now expanded into the traditional areas of anthropology, economics, and political science with the study of non-Western societies, culture, economic activity and politics (just as, in many cases, those disciplines extended into the traditional areas of sociology).
See main article: Sociology of the Internet. The Internet is of interest to sociologists in various ways. The Internet can be used as a tool for research (for example, conducting online questionnaires), a discussion platform, and as a research topic. Sociology of the Internet in the broad sense includes analysis of online communities (i.e. newsgroups, social networking sites) and virtual worlds. Organizational change is catalyzed through new media like the Internet, thereby influencing social change at-large. This creates the framework for a transformation from an industrial to an informational society. Online communities can be studied statistically through network analysis and at the same time interpreted qualitatively through virtual ethnography. Social change can be studied through statistical demographics, or through the interpretation of changing messages and symbols in online media studies.
See main article: social research. Methods of sociological inquiry vary. The type of methodology used researching sociology is predicated upon the theoretical orientation of the researcher(s). The basic goal of sociological research is to understand the social world in its many forms. Quantitative methods and qualitative methods are two main types of sociological research. Sociologists often use the quantitative methods, such as social statistics or network analysis to investigate the structure of a social process or describe patterns in social relationships. Sociologists also often use the qualitative methods such as focused interviews, group discussions and ethnographic methods to investigate social processes. Sociologists also use applied research methods such as evaluation research and assessment.
The following list of research methods is neither exclusive nor exhaustive. Researchers may adopt one or more than one type of research methodology for a research project. Types of research methods include the following:
sometimes referred to as "Historical Method". This research uses information from a variety of historical records such as biographies, memoirs and news releases.
The contents of interviews and questionnaires are analyzed using systematic approaches. An example of this type of research methodology is known as "grounded theory." Books and mass media are also analyzed to study how people communicate and the messages people talk or write about.
The researcher isolates a single social process or social phenomena and uses the data to either confirm or construct social theory. Participants (also referred to as "subjects") are randomly assigned to various conditions or "treatments", and then analyses are made between groups. Randomization allows the researcher to be sure that the treatment is having the effect on group differences and not any extraneous factors.
The researcher obtains data from interviews, questionnaires, or similar feedback from a set of people chosen (including random selection) to represent a particular population of interest. Survey items from an interview or questionnaire may be open-ended or closed-ended.
This is the study of the personal life trajectories. Through a series of interviews, the researcher can probe into the decisive moments or various influences in their life.
This is an extensive examination of a specific person or group over a long period of time.
Using data from the senses, one records information about social phenomenon or behavior. Observation techniques can be either participant observation or non-participant observation. In participant observation, the researcher goes into the field (such as a community or a place of work), and participates in the activities of the field for a prolonged period of time in order acquire a deep understanding of it. Data acquired through these techniques may be analyzed either quantitatively or qualitatively.
The choice of a method in part often depends on the researcher's epistemological approach to research as well as the researchers theoretical perspective. For example, researchers who are concerned with a statistical generalization to assign to a population will most likely administer structured interviews with a survey questionnaire to a carefully selected sample population. By contrast, sociologists, especially ethnographers, who are more interested in having a full contextual understanding of group members lives will choose participant observation, observation, and open-ended interviews. Many studies combine several of these methodologies. Adopting three (3) methodologies is referred to as "triangulation".
As is the case in most disciplines, sociologists are often divided into distinctive camps of support for particular research methodologies. This is based upon the researcher's theoretical orientation. In practice, some sociologists combine different research methods and approaches, since different methods produce different types of findings that correspond to different aspects of societies. For example, quantitative methods may help describe social patterns, while qualitative approaches could help to understand how individuals understand those patterns. This, however, does not mean that a qualitative approach can not identify or define patterns of behavior. Nonetheless, the method of analysis of the data obtained from a research methodology may be qualitative, quantitative or both.
Sociology shares deep ties with a wide array of other disciplines that also deal with the study of society. The fields of anthropology, economics, political science and psychology have influenced and have been influenced by sociology and these fields share a great amount of history and common research interests. Social psychology within sociology is often referred to as "sociological social psychology". Two of the founders of social psychology as we understand it today are Muzafer Sherif and Carolyn Wood Sherif, known for their work on the Robbers Cave Experiment . The Sherifs also wrote several editions of "An Outline of Social Psychology"  .
Today, sociology and other social sciences are better contrasted according to methodology rather than by objects of study. Additionally, unlike sociology, psychology and anthropology have forensic components that deal with anatomy and other types of laboratory research.
Sociobiology, is the study of how social behavior and organization has been influenced by evolution and other biological process. The field blends sociology with a number of other sciences, such as anthropology, biology, zoology, and others. Although the field once rapidly gained acceptance, it has remained highly controversial within the sociological academy. Sociologists often criticize the study for depending too greatly on the effects of genes in defining behavior. Sociologists often respond by citing a complex relationship between nature and nurture.