 When the terms are used in a scientific context, holism and reductionism refer primarily to what sorts of models or theories offer valid explanations of the natural world; the scientific method of falsifying hypotheses, checking empirical data against theory, is largely unchanged, but the method guides which theories are considered.In many cases (such as the kinetic theory of gases), given a good understanding of the components of the system, one can predict all the important properties of the system as a whole.In other systems, especially concerned with life and life's emergent properties (morphogenesis, autopoiesis, and metabolism), emergent properties of the system are said to be almost impossible to predict from knowledge of the parts of the system.