This actual correspondence between two lucid gentlemen introduces the first ever comprehensive, technically sound, demonstrable explanation for behavior: What it is, how it works, what it accomplishes.

Simply put: Living organisms--people included--are control systems, and act to experience what they want to experience. You know that is what you do, and that is what control systems do.

Perceptual Control Theory (PCT) explains how living things work. PCT lays a foundation for psychology to become a science based on clear principles no less reliable than principles employed in the...