Thesystemic is a way of defining, to study, or explain any type of phenomenon, which consists above all in considering this phenomenon as a system : a complex set of interactions, often between subsystems, all within a larger system.

It differs from traditional approaches which attempt to divide a system into parts without considering the functioning and activity of the whole., that is, the overall system itself.

The system therefore favors a global approach, macroscopic, holistic or synthetic ; she observes and studies a system from various perspectives and at different levels of organization ; and above all it takes into account the various interactions existing between the parts of the system (including any subsystems).

Gradually appeared in the mid-twentieth century, the systemic was built in opposition to the Cartesian analytical tradition and other forms of reductionism, who tend to divide the whole into independent parts and show their limits in understanding reality. Two main phases have historically been distinguished, often called "first" and "second" systemic :

The first systemic, years 1950 at 1970), is often considered static, centered around closed theoretical systems studied in France by structuralism, in the United States through cybernetics and information theory
The second systemic, from the years 1970, is born with the emergence of the concepts of emergence and self-organization, and leads to a more open and applied design of complex systems.

The term systemic is coined from the ancient Greek systema (system), "Organized group"