Why Do Logically Incompatible Beliefs Seem Psychologically Compatible?

Humans’ understanding of science is at once impressive and appalling. Humans, as a species, have uncovered the hidden causes of most natural phenomena, from rainbows to influenza to earthquakes. Unobservable causal agents, like germs and genes, have been discovered and studied and are now familiar to everyone, scientists and nonscientists alike. Even children are familiar with germs and genes, despite our ignorance of these entities for the majority of human history. On the other hand, individual humans often lack an understanding of core scientific ideas – ideas that most educated adults have encountered in books, museums, and classes but still fail to understand. National polls in the United States and other countries have revealed that millions of people believe that dinosaurs coexisted with humans, that atoms are smaller than electrons, and that the earth’s continents are fixed in place. Likewise, millions are skeptical that genetically modified foods are safe to eat, that climate change is caused by humans, and that humans evolved from nonhuman ancestors (National Science Board, 2018; Pew Research Center, 2015). Exposure to scientific ideas does not guarantee their comprehension or acceptance. While there are several reasons why scientific ideas remain elusive, one primary reason is that they conflict with the explanations we devise on our own about how the world works (Carey, 2009; Shtulman, 2017; Vosniadou, 1994). These explanations, termed “folk theories” or “intuitive theories,” are typically constructed in childhood prior to any formal instruction in the relevant domain. They are derived from a combination of inputs – innate concepts, empirical observations, culturally transmitted beliefs – and they serve the same function as scientific theories, namely, furnishing us with systematic and coherent inferences about natural phenomena (though see DiSessa, 2008, for an alternative view of how conceptual knowledge is structured).