“If a child grows to adulthood with a verbal world in his head which corresponds fairly closely to the extensional world that he finds around him in his widening experience, he is in relatively small danger of being shocked or hurt by what he finds, because his verbal world has told him what, more or less, to expect. He is prepared for life. If, however, he grows up with a false map in his head – that is, with a head crammed with error and superstition – he will be constantly running into trouble, wasting his efforts and acting like a fool.”

-S. I. Hayakawa[1]

Research in several academic fields, especially in the last few decades, has given us a new perspective on our own minds. These are the fields at the confluence of science and philosophy: fields like experimental psychology, probability theory, decision theory, information theory and artificial intelligence. In these disciplines we have begun to examine human reasoning and knowledge itself, and to attempt to explain how they work. Here we have developed powerful tools for understanding our world. Rationality is about applying these tools to our thoughts and actions in order to systematically optimize our lives and our world.

As it turns out, evolution has not provided us with good natural rationality instincts, and most of the time we wield the tools of rationality rather clumsily if at all. Experimental psychology has identified a large number of cognitive biases – bugs in our reasoning software – that we are susceptible to[2]. We see patterns in randomness, and causality where there is none[3]. We tend to accept the myths and superstitions of our social and cultural groups without considering the reasoning behind these beliefs. We choose leaders based on factors like their enthusiasm, charisma and even the shape of their face[4] rather than characteristics that would actually qualify them to make our most important decisions. We tend to first form beliefs based on gut instinct and then afterward go about trying to find reasons to justify them, rather than letting reasons lead us to beliefs[5]. We tend to make decisions emotionally instead of using our faculties of reason[6]. Perhaps worst of all, we are mostly blind to all of this, and tend to believe we choose our beliefs and make our decisions more rationally than we really do[7]. But we do have faculties of reason, and we can learn to use them better.

From experimental psychology we can learn how our biases can cause wrong thinking and bad decisions. From probability theory we can learn to correctly draw conclusions from observations and make the best use of the information available to us. From decision theory we can learn how to best allocate our resources and make choices that lead to the best outcomes. By identifying the bugs and inadequacies in our brain’s reasoning software and by learning better methods of reasoning we can effectively upgrade our brain’s reasoning software, what cognitive scientist Keith Stanovich calls our mindware[8].

As ideas spill over from the research world and diffuse through the general public, rationality has been slowly spreading into a minor social movement. Popular books about probability, inference, human reasoning, logical fallacies, social psychology and other topics relevant to human rationality have began to appear on bestseller lists[9]. There are even meetup groups organized in dozens of cities that meet regularly to discuss and practice being more rational[10].

“I’m not being all that fanciful or idealistic in saying that we are in many ways trembling on the threshold of a far deeper understanding of ourselves than ever before… Given how much of our view of the world is shaped by our perceptions and the way we filter information as it reaches us, clarifying our understanding of that filter is bound to significantly reshape our relationship to the world.”

-Raph Koster[11]

Despite its growing popularity, it is probably best not to think about rationality as a group or movement to join. A social movement will inevitably gather its own leaders, beliefs and group norms, and the idea of rationality is somewhat antithetical to that. Rationality is about no more than taking the information you receive from your senses and using that information in an optimum way. Ideally, rationality has no official position on any particular belief; it only demands consistency in the reasoning connecting those beliefs with your state of knowledge. A person may apply the ideas of rationality to answer specific questions about the world, but rationality itself has no built-in answers to specific questions.

Rationality is about trying to achieve the best possible correspondence between our beliefs about the world and the world itself, and to then use these beliefs to inform our decisions so that our actions tend to lead to the best outcomes. Modern science and philosophy has discovered powerful tools to help us achieve these goals. If we use them, and encourage others to do so, perhaps we can make ourselves and our world more rational.