Introduction and theoretical framework
It is evident that the human species is highly intelligent and well adapted. Some of our intelligence we clearly share with many other animals: we have well-developed visual and other perceptual systems, complex motor skills and the ability to learn in many ways to adapt to the environment around us. We also seem to be smart in ways that other creatures are not: we have a language system that is complex and sophisticated in its ability both to represent knowledge and to communicate with other humans; we study and attempt to understand a multitude of subjects including our own history and that of the universe; we have devised systems of mathematics and logic; we design and build a huge range of structures and artifacts; we have constructed and mostly live our lives within highly complex economic and social structures. All of these distinctively human things imply an extraordinary ability to reason, entertain hypotheses and make decisions based upon complex mental simulations of future possibilities. I will use the term “hypothetical thinking” as a catch-all phrase for thought of this kind.