Dealing with Complexity

Image credit: istockphoto: 19814069, by Ma_co.


Health depends on the proper functioning of complex biological systems responsive to multiple environmental effects, and understanding disease depends on analyzing how complex systems go awry. In many circumstances we are beyond the simple analysis of component “A” goes up and then component ”B” goes down. Single lines on gel blots will become relics  of our past. Some  may wish that  they lived and performed science in the era of gold standard Koch postulates, but that is not our time. As mentioned in previous blogs we now require more complex mathematical analysis and constructs that either we learn to perform ourselves or for which we seek knowledgeable and state-of-the-art collaborators.  Three recent methodology articles bear reviewing first by yourself and them with a wise colleague.

In a review in Science (Brennan et al, 2012), signaling and heterogeneity in cell populations and the variability (noise) seen in systems is considered from the standpoint of basic information theory. Theories on how cells or groups of cells get optimal information at the minimum metabolic cost are considered. No equations in this one, so breathe easily.

In the same issue, Scheffer et al (2012) consider critical transitions in systems and how heterogeneous systems may be considerably robust and resilient — and adaptive to multiple stresses. There are examples from chemistry and physiology to ecology.

Finally, the question of causality is approached — and avoiding the traps of  inferring causality from correlation (Sugihara et al, 2012).  This is a timely topic in these days of interpreting  the fall elections. Discussed in detail are the relationships between anchovy populations and sardine populations in  the Pacific ocean. These are questions that may not be approached through experiments.

I suggest that the first step is to develop seminar series that may be beyond the usual comfort levels of clinical or basic scientists so that these types of analyses can be explored with new groupings of smart folks. A modest idea.



Brennan MD, Cheong R, Levchenko A, et al. How Information Theory Handles cell signaling and uncertainty Science 338:334-5, 2012

Scheffer M , Carpenter SR, Lenton TM, et al. Anticipating critical transitions. Science 338:344-8, 2012

Sugihara G , May R, Ye H, et al. Detecting Causality in Complex Ecosystems Science 338:496-500, 2012

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