Holism (from Greek ὅλος holos “all, whole, entire”) is the idea that systems (physical, biological, chemical, social, economic, mental, linguistic, etc.) and their properties should be viewed as wholes, not as collections of parts. This often includes the view that systems function as wholes and that their functioning cannot be fully understood solely in terms of their component parts.
Holism is a form of antireductionism, which is the complement of reductionism. Reductionism analyzes a complex system by subdividing or reduction to more fundamental parts. For example, the processes of biology are reducible to chemistry, and the laws of chemistry are explained by physics.
Social scientist and physician Nicholas A. Christakis explains that “for the last few centuries, the Cartesian project in science has been to break matter down into ever smaller bits, in the pursuit of understanding. And this works, to some extent… but putting things back together in order to understand them is harder, and typically comes later in the development of a scientist or in the development of science.”