Systems biology may work when we learn to understand the parts in terms of the whole.

The first point to note about whether systems biology will work is that the essential idea of systems biology is not new: there has been interest in it, as well as efforts to apply it, since the middle of the 20th century. The difference now is that it has become fashionable, with an explosion in the number of publications using the two words, albeit not always with the same meaning. The reductionist approach remains dominant, however, and systems biology is often seen as no more than integration of diverse data into models of systems. This way of thinking needs to be changed if systems biology is to lead to an understanding of life and to provide the benefits that are expected from it. The emphasis ought to be on the needs of the system as a whole for understanding the components, not the converse. General properties of metabolic systems, such as feed-back inhibition, can be properly understood by taking account of supply and demand, i.e. the requirements of the system as a whole, but this is often overlooked. Metabolism tends to be viewed as static, although enzymes (and proteins in general) are continuously synthesized and degraded. The fact that they are themselves therefore metabolites introduces great complexity to metabolism, including an implication of infinite regress; understanding how living organisms escape from this will be an essential step towards understanding life.