Sociology is the scientific study of society that focuses on social class, culture, law, health, and deviance through empirical investigation and critical analysis. It aims to understand human social activities and determine laws governing human behaviors by distinguishing them from social processes. Some key contributors include Plato, Auguste Comte, Karl Marx, and Emile Durkheim. Common research methods include quantitative methods like experiments and surveys as well as qualitative methods like observation. Major challenges include addressing subjectivity, inconsistency, and individual differences when studying humans and society.