Brooks and Suzanne Ragen Professor of Psychology, Yale University; Author, Against Empathy

We are powerfully influenced by irrational processes such as unconscious priming, conformity, groupthink, and self-serving biases. These affect the most trivial aspects of our lives, such as how quickly we walk down a city street, and the most important, such as who we choose to marry. The political and moral realms are particularly vulnerable to such influences. While many of us would like to think that our views on climate change or torture or foreign policy are the result of rational deliberation, we are more affected than we would like to admit by considerations that have nothing to do with reason. 

But this is not inevitable. Consider science. Plainly, scientists are human and possess the standard slate of biases and prejudices and mindbugs. This is what skeptics emphasize when they say that science is "just another means of knowing" or "just like religion". But science also includes procedures — such as replicable experiments and open debate — that cultivate the capacity for human reason. Scientists can reject common wisdom, they can be persuaded by data and argument to change their minds. It is through these procedures that we have discovered extraordinary facts about the world, such as the structure of matter and the evolutionary relationship between monkey and man.

The cultivation of reason isn't unique to science; other disciplines such as mathematics and philosophy possess it as well. But it is absent in much of the rest of life. So I admit to twisting the question a bit: The concept that people need to add to their toolkit isn't a scientific discovery; it is science itself. Wouldn't the world be better off if, as we struggle with moral and political and social problems, we adopted those procedures that make science so successful?