The reason folk science so often gets it wrong is that we evolved in an environment radically different from the one in which we now live. Our senses are geared for perceiving objects of middling size–between, say, ants and mountains–not bacteria, molecules and atoms on one end of the scale and stars and galaxies on the other end. We live a scant three score and 10 years, far too short a time to witness evolution, continental drift or long-term environmental changes.
Causal inference in folk science is equally untrustworthy. We correctly surmise designed objects, such as stone tools, to be the product of an intelligent designer and thus naturally assume that all functional objects, such as eyes, must have also been intelligently designed. Lacking a cogent theory of how neural activity gives rise to consciousness, we imagine mental spirits floating within our heads. We lived in small bands of roaming hunter-gatherers that accumulated little wealth and had no experience of free markets and economic growth.
Folk science leads us to trust anecdotes as data, such as illnesses being cured by assorted nostrums based solely on single-case examples. Equally powerful are anecdotes involving preternatural beings, compelling us to make causal inferences linking these nonmaterial entities to all manner of material events, illness being the most personal. Because people often re-cover from sickness naturally, whatever was done just before recovery receives the credit, prayer being the most common.
via bird on the moon