When he was sixteen years old, Albert Einstein imagined that he was chasing after a beam of light and observed what he “saw.” And this vision launched him on the path to developing his theory of special relativity. Einstein often engaged in such thinking; he reported: "…The psychical entities which seem to serve as elements in thought are certain signs and more or less clear images which can be ‘voluntarily’ reproduced and combined... this combinatory play seems to be the essential feature in productive thought before there is any connection with logical construction in words or other kinds of signs which can be communicated to others..."
Einstein was relying on mental emulation, a kind of thought that many of us use and we all probably could use more frequently—and more productively—if we become aware of it. Mental emulations range from the sublime to the ordinary, such as imagining currently impossible events (including chasing after a beam of light), or imagining the best route to take when climbing up a hill, or visualizing the best way to pack your refrigerator before starting to take cans, boxes and jugs out of your shopping bag.
A mental emulation is a way to simulate what you would expect to happen in a specific situation. Just as Einstein reported, most mental emulations appear to involve mental imagery. By definition, mental imagery is an internal representation that mimics perception. You can visualize “running” an event in your head, and “seeing” how it unfolds. Mental emulations are partly a way of allowing you to access knowledge that you have only implicitly, to allow such knowledge to affect your mental images.
My colleague Sam Moulton and I characterize mental emulation as follows: Each step of what you imagine represents the corresponding step in the real world, and the transitions between steps represent the corresponding transitions between steps in the event. Moreover, the processes that transition from state to state in the representation mimic the actual processes that transition from state-to-state in the world. If you imagine kicking a ball, you will actually activate motor circuits in the brain, and neural states will specify the transitional states of how your leg is positioned as you kick. And as you imagine tracking the flying ball, your mental images will transition through the intermediate states in ways analogous to what would happen in the real world.
Mental emulation is a fundamental form of thought, and should be recognized as such.