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The Tree of Knowledge System is a novel, theoretical approach to the unification of psychology developed by Gregg Henriques, Ph.D., Assistant Professor, Combined-Integrated Doctoral Program, James Madison University, Harrisonburg, VA, USA.

The outline of which was published in 2003 in Review of General Psychology and two special issues of the Journal of Clinical Psychology in Dec 04 and Jan 05 were devoted to the elaboration and evaluation of the model.

The problem of psychology

The most difficult problem in Psychology as a discipline is that while there is incredible diversity offered by different approaches to psychology, there is no overall consensus model of what Psychology actually is.

According to the ToK System, the problem of psychology is that

a clear definition, an agreed upon subject matter, and a coherent conceptual framework have eluded its students for its entire 125 year history... The patent tendency [of psychology] has been toward theoretical and substantial fractionation and increasing insularity among the “specialities”

In other words, the discipline has fragmented into different schools of thought and methodology, with no overall framework to interpret and integrate the research of different areas. At its best, the different approaches are a strength of psychology; different approaches lead to novel ideas, and prevent psychologists from clinging to a paradigm that fails to explain a phenomena. At its worst, adherents of one particular school cling to their beliefs concerning the relative importance of their research and disregard or are ignorant of different approaches. In most cases, the individual Psychologist has to determine for themselves which elements of which perspective to apply, and how to integrate them into their overall understanding.

The reason for this "fractionation," according to the ToK, is because:

...psychology connects to each of the "three great branches of learning." More than any other discipline, it is an admixture of natural science, social science, and humanism. Thus a coherent vision for psychology will provide the conceptual infrastructure for a coherent linkage between the natural and social sciences and the humanities.
(Both quotes cited from The Official ToK System website)

In other words, the human mind is being influenced from the outside by environment and culture (humanities) as well as from the inside, by hormones, physiology of the brain, and ultimately genetics (biology). The Tree of Knowledge system attempts to determine the correct position for Psychology in relation to these other disciplines. The picture below helps to illustrate this.

Tree of Knowledge

The Tree of Knowledge Diagram. Adapted from Presentation on The Official ToK System website.

The Tree of Knowledge separates the world of knowledge into 4 layers of complexity, which have evolved throughout the history of the Universe, since the Big Bang.


Matter and Energy are theorized to have effectively began at the Big Bang. It is possible that a Theory of Quantum gravity may one day explain how this occured, but at present such a theory does not exist. The study of matter and energy at its most fundamental level is the academic discipline of physics.

At more complicated levels, the discipline of Chemistry is a more suitable method of description. Chemistry at the molecular level however, is really just complicated Physics, but it is too complicated to explain using normal physical models, so chemical diagrams, synthesis routes and the like are used instead.


Life is theorized to have occured when complex, self replicating molecules formed something equivalent to DNA. It is possible that a Theory of Gene formation may one day explain how this occured, but at present such a Theory does not exist. The study of Life at its most fundamental level is the academic discipline of Genetics. Note that Genetics is really just complicated Chemistry.

At a more complicated level, the discipline of Biology is a more suitable method of description. Biology at a cellular level however, is really just complicated Genetics, but it is too complicated to explain using normal Molecular genetic models, and so cell diagrams, abbreviated protein and enzyme types, and biological diagrams are used instead.

Note that Biology is just very complicated Physics, but biology is too complicated for physics to explain.


Mind (or the experience of awareness) can be theorized to have occured when the first creature with a complicated enough brain realized that it was aware of its thoughts (metacognition). No one to date has a suitable theory to explain how this came to be, and there are disagreements as to what sentience really is. Is a spider sentient? or a Cat? What about a Chimpanzee or an unborn human? The theory of how mind came to be is a spiritual matter. In any case, the study of Mind at its most fundamental level is Biopsychology. Note that Biopsychology (a bottom up, or inside out approach) is really just complicated Biology.

At a more complicated level, there is the effect of the external environment on the mind, which is able to adapt and change according to environmental input (at least for human beings and conditionable animals). The effect of the environment on the mind is hard to determine directly, but the effect of the environment on Behaviour is the Psychological approach of Behaviourism. Note that behaviourism (a top down, or outside in apprach) is the really just the complicated sociological influence on behaviour on the individual.

In the middle of these two extremes are the cognitive processes and self aware thoughts that make up the Human Being. Approaches that describe this in between level are the Psychoanalytic approach of Freud et al, the cognitive processes of Cognitive psychology and the Humanistic approach of Rogers, Maslow and Spiritual approaches such as Abhidharma (in Buddhism) and all other world spiritual paths and religions.

Note that all of these approaches are really just the complicated interaction of very, very complicated physics on more, very very complicated physics. But physics is not a good model to explain such complexity.


Culture is what arises when human beings, capable of language (or at least communication) begin to pass ideas from one mind to another in the form of cultural transfer, or tools of intellectual adaptation, (Vygotsky). The study of culture at its most fundamental level is part of the academic disciplines of sociology and anthropology.

At more complicated levels, the study of Art, Music, Politics, Warfare, Love, Happiness and Religion are all part of culture. They are all essentially very complicated sociology however, but so complicated that it is only sensible to study these areas as subjects in their own right, remembering how they link together.

Note that all of these subjects are really just very, very, very complicated Physics. But Physics is not a good model to explain them well at this level.

Theoretical joint points

Currently, no adequate theories exist to explain the 'joint points' between the seperate areas of Matter, Life, Mind and Culture. Perhaps one reason for this is that they are not fundamentally different from one another. The culture of Art really IS just very, very, very complicated physics (a lot more verys are required to be honest).

However, different models must be used at the different levels, not just because of increasing levels of complexity, but also because of emergent phenomena. An example of an emergent phenomena is a flock of pidgeons. No single pidgeon has the capability of directing or even understanding

Quantum Gravity

Main article: Quantum Gravity

Wikipedia - Quantum Gravity

The Modern Synthesis

Main article: The Modern Synthesis

Behavioral Investment Theory (BIT)

Main article: Behavioral Investment Theory

The Justification Hypothesis (JH)

Main article: The Justification Hypothesis

See also


Further reading

External Links