ABSTRACT
This chapter considers work by psychologists that has given some understanding of a particular limitation which is believed to have greatly affected advances in the history of science. Human beings are able to solve mental problems by using a process that, in several respects, is analogous to making relevant observations of physical objects in their environment. In the history of science, one might expect a progression to be apparent from theories which are easily conceived to ones which are less easily conceived, with the latter presumably being thought of only when the former fail to yield correct predictions. Hence, for humans, one might expect a progression in scientific theories from those that refer to entities which have the sensory characteristics of perception to more abstract entities which do not have sensory characteristics and therefore cannot be imagined. Science begins with the formulation of the most easily conceived theories and moves to less easily conceived theories only when easy theories fail.
