Historicism is an approach to explaining the existence of phenomena, especially social and cultural practices (including ideas and beliefs), by studying their history; that is, by studying the process by which they came about. The term is widely used in philosophy, anthropology, and sociology.
This historical approach to explanation differs from and complements the approach known as functionalism, which seeks to explain a phenomenon, such as for example a social form, by providing reasoned arguments about how that social form fulfills some function in the structure of a society. In contrast, rather than taking the phenomenon as a given and then seeking to provide a justification for it from reasoned principles, the historical approach asks "Where did this come from?" and "What factors led up to its creation?"; that is, historical explanations often place a greater emphasis on the role of process and contingency.
Historicism is often used to help contextualize theories and narratives, and is a useful tool to help understand how social and cultural phenomena came to be.
The historicist approach differs from individualist theories of knowledge such as strict empiricism and de-contextualised rationalism, which neglect the role of traditions. Historicism may be contrasted with reductionist theories—which assume that all developments can be explained by fundamental principles (such as in economic determinism)—or with theories that posit that historical changes occur entirely at random.
David Summers, building on the work of E. H. Gombrich, defines historicism negatively, writing that it posits "that laws of history are formulatable and that in general the outcome of history is predictable," adding "the idea that history is a universal matrix prior to events, which are simply placed in order within that matrix by the historian." This approach, he writes, "seems to make the ends of history visible, thus to justify the liquidation of groups seen not to have a place in the scheme of history" and that it has led to the "fabrication of some of the most murderous myths of modern times."
2. There is also a certain historicism, which attributing value only to the events of man's life, overthrows the foundation of all truth and absolute law both on the level of philosophical speculations and especially to Christian dogmas. (Papal Encyclical, Humani Generis, 12 August 1950).