“From the Big Bang to the whole shebang: quantum gravity, the modern evolutionary synthesis, B.F Skinner and Sigmund Freud, the ToK connects huge pieces of the puzzle of knowledge and offers new, unified picture that could revolutionize, well, almost everything.”

Since its inception as an independent discipline, the field of psychology has had serious difficulty developing a unified theoretical formulation and a clear definition of its subject matter. And it has also struggled to define its relationship to other sciences. For example, many individuals see psychology as a natural science, others see it as a social science, and still others question whether it is a science at all. Related to the confusion surrounding its definition is the fact that, perhaps more than any other discipline, psychology exists at the intersection of the three great branches of learning: the natural sciences, the social sciences, and the humanities. So when a paper such as the one I offered purports to define psychology, it attracts a lot of interest.

The clear definition and theoretical unification of psychology is achieved through the introduction of a new scientific humanistic philosophy called the Tree of Knowledge (ToK) System. The ToK System is a theory of the evolution of complexity as presently mapped out by science. It takes the spectrum of what we know (and what we think we know) and systematizes it into four distinct hierarchically arranged levels of complexity: Matter, Life, Mind, and Culture. This novel depiction of cosmic evolution is used to show how psychology corresponds to the dimension of Mind and how it connects to biology (which corresponds to the dimension of Life) from below, and to the social sciences (which corresponds to the dimension of Culture) from above.

Stephen Hawking wrote that if we discovered the "ultimate theory of the universe…it would bring an end to a long and glorious chapter in the history of humanity’s intellectual struggle to understand the universe" and would "revolutionize the ordinary person’s understanding" of how the world works. I believe the ToK System represents a crucial step in this direction. It is essentially a theory of theories that streamlines human knowledge into an integrated, coherent system. From the Big Bang to the whole shebang—quantum gravity, the modern evolutionary synthesis, B.F Skinner, and Sigmund Freud—the ToK connects huge pieces of the puzzle of knowledge and offers a new, unified picture that could revolutionize, well, almost everything.

Just over 10 years ago I became increasingly appalled and discouraged by the state of psychology. Trained as a clinician, I wanted to be sure that the psychotherapy I provided was grounded in a coherent empirically supported theoretical understanding of human behavior. Yet as I progressed through my doctoral training, it became clear to me that, at a theoretical level, psychology was a mess. The dominant perspectives such as cognitive science, behavioral science, psychodynamic theory, social constructionist views, evolutionary psychology, neuroscience, humanistic approaches, and so on, clearly had crucial things to say. Yet when one surveyed the discipline as a whole, the only general conclusion was that psychology was a buzzing mass of confusion. So, for my own edification, I surveyed a broad array of literatures. Ultimately, a model emerged that is broader and more successful at organizing knowledge than I would have ever dreamed possible.