Disease is a condition which arises in a living organism, animal or plant, where something malfunctions and impairs the normal operation of the organism. In "systems" terms, disease represents a disruption of one or more parts of a biological system, which in turn disrupts the interactions among various parts of the system, and thus compromises one or more of the system´s functions (i.e., one or more of the system´s emergent properties). You might not think of it this way when dealing with a headache, but scientists have this perspective when studying the normal function of organisms.

Developing an understanding of the factors that cause disease motivates much of biological research. Historically, biologists studied organisms "from the bottom up". Because the complexity of biological systems can be overwhelming (even when studying a single human cell), scientists elected to dissemble the systems and study them, part by part, with the hope that the sum of their knowledge about the parts would help to explain the operation of the whole. Rarely has that been a successful strategy to understand the causes and cures for complex diseases, such as cancer.

All biological organisms exhibit systems properties - properties which arise from many parts interacting as a whole, and which cannot arise from any single part. Because of the potential complexity of a whole system, to truly understand biological organisms they must be studied as whole systems. As we saw with the light bulb, its function can be understood only by studying all the parts together. We also must view the parts of an organism (including humans) as elements interacting in a unified system to fully understand that organism. This is the inspiration and driving motivation for systems biology and our research at the ISB.