Biological Causes

Modern biology is characterized by a number of ideological prejudices that shape the form of its explanations and the way its researches are carried out. One of those major prejudices is concerned with the nature of causes. Generally one looks for the cause of an effect, or even if there are a number of causes allowed, one supposes that there is a major cause and the others are only subsidiary. And in any case, these causes are separated from each other, studied independently, and manipulated and interfered with in an independent way. Moreover, these causes are usually seen to be at an individual level, the individual gene or the defective organ or an individual human being who is the focus of internal biological causes and external causes from an autonomous nature.

This view of causes is nowhere more evident than in our theories of health and disease. Any textbook of medicine will tell us that the cause of tuberculosis is the tubercle bacillus, which gives us the disease when it infects us. Modern scientific medicine tells us that the reason we no longer die of infectious diseases is that scientific medicine, with its antibiotics, chemical agents, and high-technology methods of caring for the sick, has defeated the insidious bacterium. What is the cause of cancer? The cause is the unrestricted growth of cells. That runaway growth, in turn, is a consequence of the failure of certain genes to regulate cell division. So we get cancer because our genes are not doing their business. It used to be that people thought that viruses were a major cause of cancer, and a great deal of money and time has been spent looking for the viral causes of cancer in humans without success. Biology has moved on from the time when viruses were all the rage to a time when genes are much more trendy.

Alternatively, there are environmental insult theories of the causes of cancer. Cancers are caused, we are told, by asbestos or by PVC or by a host of natural chemicals over which we have no control, and although they are present in very low concentrations, we are exposed to them over our whole lives. So, just as we will avoid dying from tuberculosis by dealing with the bug that causes it, so we will avoid dying from cancer by getting rid of particularly nasty chemicals in the environment. It is certainly; true that one cannot get tuberculosis without a tubercle bacillus, and the evidence is quite compelling that one cannot get the cancer mesothelioma without having ingested asbestos or related compounds. But that is not the same as saying that the cause of tuberculosis is the tubercle bacillus and the cause of mesothelioma is asbestos. What are the consequences for our health of thinking in this way? Suppose we note that tuberculosis was a disease extremely common in the sweatshops and miserable factories of the nineteenth century, whereas tuberculosis rates were much lower among country people and in the upper classes. Then we might be justified in claiming that the cause of tuberculosis is unregulated industrial capitalism, and if we did away with that system of social organization, we would not need to worry about the tubercle bacillus. When we look at the history of health and disease in modern Europe, that explanation makes at least as good sense as blaming the poor bacterium. -- Biology as Ideology, Richard Lewontin