We thought we had this one nailed. Believing (rightly) that the physical world is all there is, the sciences of the mind re-invented thought and reason (and feeling) as information-processing events in the human brain. But this vision turns out to be either incomplete or fatally flawed. The neat and tidy division between a level of information processing (software) and of physicality (implementation) is useful when we deal with humanly engineered systems. We build such systems, as far as possible, to keep the levels apart. But nature was not guided by any such neat and tidy design principles. The ways that evolved creatures solve problems of anticipation, response, reasoning and perceiving seem to involve endless leakage and interweaving between motion, action, visceral (gut) response, and somewhat more detached contemplation. When we solve a jigsaw puzzle, we look, think, and categorise: but we also view the scene and pieces from new angles, moving head and body. And we pick pieces up and try them out. Real on-the-hoof human reason is like that through and through. Even the use of pen and paper to construct arguments displays the same complex interweaving of embodied action, perceptual re-encountering, and neural activity. Mind and body (and world) emerge as messily and continuously coupled partners in the construction of rational action.
But this leads to a very real problem, an impasse that is currently the single greatest roadblock in the attempts to construct a mature science of the mind. We cannot, despite the deep and crucial roles of body and world, understand the mind in quite the same terms as, say, an internal combustion engine. Where minds are concerned, it is the flow of contents (and feelings) that seems to matter. Yet if we prescind from the body and world, pitching our stories and models at the level of the information flows, we again lose sight of the distinctively human mind. We need the information-and-content based story to see the mind as, precisely, a mind. Yet we cannot do justice to minds like ours without including body, world (cognitive tools and other people) and motion in roles which are both genuinely cognitive yet thoroughly physical.
What we lack is a framework, picture, or model in terms of which to understand this larger system as the cognitive engine. All current stories are forced to one side (information flows) or the other (physical dynamics). Cognitive Science thus stands in a position similar to that of Physics in the early decades of the 20th century. What we lack is a kind of 'quantum theory' of the mind: a new framework that displays mind as mind, yet as body in action too.