When you open your eyes in the morning, you usually see what you expect to see. Often it will be your bedroom, with things where you left them before you went to sleep. What if you opened your eyes and found yourself in a steaming tropical jungle? or a dark cold dungeon? What a shock that would be! Why do we have expectations about what is about to happen to us? Why do we get surprised when something unexpected happens to us? More generally, why are we Intentional Beings who are always projecting our expectations into the future? How does having such expectations help us to fantasize and plan events that have not yet occurred? How do they help us to pay attention to events that are really important to us, and spare us from being overwhelmed by the blooming buzzing confusion of daily life? Without this ability, all creative thought would be impossible, and we could not imagine different possible futures for ourselves, or our hopes and fears for them. What is the difference between having a fantasy and experiencing what is really there? What is the difference between illusion and reality? What goes wrong when we lose control over our fantasies and hallucinate objects and events that are not really there? Given that vivid hallucinations are possible, especially in mental disorders like schizophrenia, how can we ever be sure that an experience is really happening and is not just a particularly vivid hallucination? If there a fundamental difference between reality, fantasy, and illusion, then what is it?
Recent models of how the brain controls behavior have begun to clarify how the mechanisms that enable us to learn quickly about a changing world throughout life also embody properties of expectation, intention, attention, illusion, fantasy, hallucination, and even consciousness. I never thought that during my own life such models would develop to the point that the dynamics of identified nerve cells in known anatomies could be quantitatively simulated, along with the behaviors that they control. During the last five years, ever-more precise models of such brain processes have been discovered, including detailed answers to why the cerebral cortex, which is the seat of all our higher intelligence, is organized into layers of cells that interact with each other in characteristic ways.
Although an enormous amount of work still remains to be done before such insights are fully developed, tested, and accepted, the outlines already seem clear of an emerging theory of biological intelligence, and with it, the scaffold for a more humane form of artificial intelligence. Getting a better understanding of how our minds learn about a changing world, and of how to embody their best features in more intelligent technologies, should ultimately have a transforming effect on many aspects of human civilization.