A Scale of Difficulty of Comprehension

John Barry, in the opening chapter of his book, The Great Influenza: The Epic Story of the Deadliest Plague In History, points out a great difference between biomedical sciences and the physical sciences. Astronomy, physics and chemistry made their great leaps forward dealing with systems that are relatively simple, and that obey relatively straightforward laws that can be expressed in mathematical equations. Biomedical sciences seek to understand systems that evolved, adapting the preexisting structures and machinery to new functions over and over again. As a result, evolved systems do not function simply, and are not easily described.

He uses the example of building a house today, using the best available technology, to achieve energy efficiency. That is compared to retrofitting a centuries old house to improve its energy efficiency. The functioning of the first would probably be much more intuitive and easy to describe than the functioning of the latter, with its centuries of accumulated modifications designed for different times and different purposes.

Perhaps Barry underestimates the complexity of modern cosmology, but I think his point is interesting and useful. Evolved systems don’t necessarily compartmentalize functions into different, easy to understand anatomical units, and, like the panda’s thumb, don’t always come up with elegant solutions (at least to those who don’t understand the starting point and the path that led to the solution). (And perhaps we would have a different mathematics if calculus had not evolved to describe bodies in motion, and we would today be concerned that physical motion was not easy to describe with the computer programs designed to model complex systems.)

When studying infectious processes, the biomedical researcher is confronted with not only the evolution of the human host, but of the virus, bacteria, fungus or parasite. Indeed, the coevolution of human and parasite seems to me to present special difficulties as both organisms have structure and process that are cobbled together from the parts made available by previous evolution, but influenced not only by the internal needs of the one organism, but by the history of responses of the other. The case of STDs suggests that the biomedical scientist have to face not only the biology of the disease, but its sociology.

Not only are biological systems evolved, but they are homeostatic – they have processes that seek to keep internal conditions uniform even as external conditions change. You infect an animal, and its immune system fights the infection (in ways that are largely invisible). You damage an organ, and the body adapts to replace the organ's function or to minimize the impact of its loss. Homeostasis makes life hard for biomedical scientists. Look how difficult it is to do nutrition research, or to understand the physiological effects of pollutants.

I am a fan of the TV show, House. It points out that “patients always lie”. Think how hard that makes life for the doctor. Not only is he dealing with an evolved, homeostatic system, but one with a will of its own, who lies to the doctor about the things which may or may not have caused the medical problem.

Which brings me to social systems. Many consider social systems to be planned, and indeed planning is an important part of the development of social systems. But I am a believer in theories of limited rationality, and I find that many social systems have structures and behavior that their members do not fully understand; these systems evolve over time in response to external influences and to the choices made by their members with incomplete information and understanding. If anything, the interplay of planning with incomplete information, the accomodation of conflicting interests by satisficing compromises, and unplanned change due to feedback and selection processes built into the social systems themselves would seem to make social systems even more difficult to understand than pure evolutionary systems that one might study in simple organisms. The pseudo rationality of leaders seeking to explain the changes that occur as the sole result of planning, combined with the rhetoric needed to justify or gain support for policies, seems to make the situation still more difficult to study.

Not only does one have to understand their history to have a fair chance of understanding how social processes have evolved and thus how they work, but those social systems too have evolved homeostatic and evolutionary mechanisms that are subtle and often difficult to understand. Moreover, societies are composed of actors with wills of their own, who will often deliberately or incidentally deceive the student of society. And the student is him/herself a member of a culture, with his/her own cultural blinders. Amazing, when you think about it, that we have any social science at all!

This blog is generally on the theme of "knowledge for development". This rant is simply to point out how complex the world is. As we seek, for example, to make health policy for developing nations, we are confronted not only with the difficulties of understanding the human body, the disease agent and their interplay, but the social factors involved. To change the situation, we are will advised to understand the social institutions involved, including those of the health service systems and the larger economic, social and political systems in which they are embedded. The farther up the chain we go, the more challenged the scientists who are working to provide us the basic understand on which to build our policies and technologies.