John Berger found his country doctor John Sassall averse to common sense. Common sense was, for Sassall, the enemy. The GP read his journals, and took his courses, but his primary satisfaction came from patients with conditions that could not be explained by his existing knowledge base. Another form of being wrong.

In an article written with Tytti Solantaus, Michael Rutter, another doctor, a psychiatrist, reflected on the relationship between science and common sense. They take six examples of science rapidly translating into common sense revealing flaws in the evidence. Here are three of the six:

  • Studies of brain development that show the value of early (in life) intervention. The common sense interpretation resulted in resources being shifted from health care for adolescents and adults and into the early years. Later experiments, made possible by new techniques such as brain imagining, reveal significant plasticity of the brain in adulthood, the changing shape of the brain of London taxi-drivers trained to know every route in London being one of many examples.
  • Studies of family life found that even minor stresses have adverse consequences for early childhood development, making the child sensitive to future stress. The common sense interpretation was to eliminate all stress. But later experiments revealed the value of risk early in life. Brief separations from mother are a part of strong attachment and a preparedness to explore the world. Exposure to dirt and disease builds a healthy body. 
  • Studies of family breakdown showed that the effects on child development were greater when parents were unmarried. The science became common sense and led to tax incentives for marriage. Later research found that decisions to marry were shaped more by cultural context than tax incentives, and that successful parenting was possible in multiple forms of couple relationship.

Rutter and Solantaus conclude that common sense tends to be inductive. We observe the world and try and logically assess what we are seeing. Science starts with a question, sets out the potential answers to that question, and tries to disprove those answers. (An experiment that shows a hypothesis to be wrong is more valuable than one proven to be right).

They finish by referring to Peter Medawar, Nobel laureate, and a lodestar for Michael Rutter. Medawar stresses the value to science of ‘story’ (the hypotheses) and the consequent testing of the story (the experiment). Since few experiments result in clear cut answers, most result in the modification of the ‘story’ and more experiments.

In short, in science, sense is never commonly held. Only the consumers of science feel comfortable with common sense.

John Berger and Jean Mohr. A Fortunate Man: The Story of a Country Doctor

Michael Rutter and Tytti Solantaus, Translation gone awry: differences between commonsense and science. European Child and Adolescent Psychiatry, 2014).

Peter Medawar, Advice to a Young Scientist, Basic Books