There are several factors that prevent psychology to build a unified theoretical framework. First, in the history of psychological science, at least two hardly compatible traditions exist, the empirical, so-called Lockean tradition (for example, behaviorism and neo-behaviorism, neuropsychology and other objective psychological directions), and the phenomenological, so-called Kantian tradition (for example, psychoanalysis, gestalt-psychology, and parts of cognitive psychology, humanistic psychology and positive psychology). Thus, it is very difficult if not impossible to unite these two traditions both with very different conceptual systems, methods, and even subjects (behavior and neural processes versus subjective experience).

Second, psychology is suffering from a multitude of authorial theories and models. That is a situation that is strange to the mathematics and natural sciences: certainly, everybody knows of Newton, or Einstein, or Heisenberg, or Darwin, yet mathematics, physics, or biology have a unified theoretical framework. What matters is the theory and integration of theories, not the authors. In psychology, however, there are plenty of "theories" and models, that are in fact very similar, yet there is no serious will to integrate them into a unified theoretical system. Instead, we have models labeled by authors (James, Freud, Pavlov, Watson, Skinner, Maslow, Kelly, Cattell, Eysenck, etc.), or conceptual orientation (behaviorism, humanistic psychology, cognitivism, positive psychology, etc.). Thus, it is highly desirable for psychology to abandon this chaotic particularism and to build a unified scientific theoretical system.

There are several factors that prevent psychology to build a unified theoretical framework. First, in the history of psychological science, at least two hardly compatible traditions exist, the empirical, so-called Lockean tradition (for example, behaviorism and neo-behaviorism, neuropsychology and other objective psychological directions), and the phenomenological, so-called Kantian tradition (for example, psychoanalysis, gestalt-psychology, and parts of cognitive psychology, humanistic psychology and positive psychology). Thus, it is very difficult if not impossible to unite these two traditions both with very different conceptual systems, methods, and even subjects (behavior and neural processes versus subjective experience).

Second, psychology is suffering from a multitude of authorial theories and models. That is a situation that is strange to the mathematics and natural sciences: certainly, everybody knows of Newton, or Einstein, or Heisenberg, or Darwin, yet mathematics, physics, or biology have a unified theoretical framework. What matters is the theory and integration of theories, not the authors. In psychology, however, there are plenty of "theories" and models, that are in fact very similar, yet there is no serious will to integrate them into a unified theoretical system. Instead, we have models labeled by authors (James, Freud, Pavlov, Watson, Skinner, Maslow, Kelly, Cattell, Eysenck, etc.), or conceptual orientation (behaviorism, humanistic psychology, cognitivism, positive psychology, etc.). Thus, it is highly desirable for psychology to abandon this chaotic particularism and to build a unified scientific theoretical system.

To explain every mental process & behavior within a single scientific theory - from object perception to morality - would be an impressive feat. When we achieve a unified theory, it will probably be an amalgam. I feel at the core will be Information Processing, which already stretches from the lowest levels of explanation (e.g., PDP as a computational model of neural processes) to the highest (e.g., Dodge's model of aggression). Cognition is central within many domains of Psychology (e.g., CBT in Clinical, role of construal in Social, neo-Piagetian in Developmental). I imagine the strongest counter-arguments would be Evolutionary Psychology (modules) and Socio-Cultural (can't ignore culture). They have some strong points, though I am optimistic we could integrate their key accomplishments into a broader Information Processing theory. What is your answer and what motivates the question, Rey? ~ Kevin

This is a very thought provoking question. Perhaps a great starting point would be to use data science tools such as, AI algorithms that scrape the internet looking for common words and themes across the various schools of psychology and/or theories. There is definitely overlap among all psychological theory but by searching for these common elements, perhaps a new theory can be "discovered". I think the bigger question is what purpose would such a theory hold that would help simplify the understanding of psychology as we know it? Or, will a unified theory of psychology add value to the field and if so, how?

The frequentist and Bayesian approaches to statistical inference are still fighting with each other, and there is no winner in sight - we adopted them both, use them both, even blend them when reporting findings..., and maybe something similar will happen to psychology...

This is an interesting question. I think one can ask, what would be the point of such a unification? If it is ultimately to enable experiential happiness and peace, this may point to some experiential theory as the entry point. The other theories would then fit in this puzzle, explaining from different perspectives how this works even down to an electrochemical/biological perspective. I said things but did not answer. Theoretical Buddhism comes to mind.

From psychogenetics to social psychology - in short, from individual perception -emotions-thinking-speech-behavior to individual values and social interaction. In the theory of psychogenetics, I have developed a unique approach, it includes an understanding of uniqueness, heredity, natural individual weaknesses and strengths from biological to psychological and social

I believe that a Neuropsycho-analitic approach including attachment theory can provide a vast integrative view of the human experience

Strangely enough, I have been thinking about this question of late. I am not a scholar, and have only just started a diploma course in Psychology recently. However, I did purchase a book by Gregg Henriques called A New Unified Theory of Psychology

Gregg, Henriques . A New Unified Theory of Psychology 2011th Edition . SAM Ficher. Kindle Edition.

I am about to start my reading this weekend, sorry I can't add anything of real value here, but just to say this question has really piqued my interest.

Adlerian Psychology could do this because it underpins post-modern theories. This is little acknowedged in the present day, Adler predicted this situation. Adler's split with Freud did much to undermine AP's standing, as did his hands on approach and the pausity of his writings. Ansbacher and Anbacher show cased Adler's work as a psychology oof use rather than possession.

Basically, psychology is the study of human behavior and the mental processes. if you draw the line between the two i.e. behavior and mental processes; you would probably be sailing without aids to navigation in the high seas. human brain is vast like the solar system with functions that influence every aspect of our behavior. I would say that a single psychological theory would perhaps be too vague to comprehend. human behavior is still a virgin gold mine with huge deposits not yet discovered not to mention the brain and its mental capabilities. single most theory in psychology is simply an understatement of the school and cannot form a unified thought all together. lastly, every discipline recognizes an authority behind every noble speculation that have formed the basis of our knowledge and study .These authorities did not converged into mono think tank but have shared their ideologies to foster and expand their area of study; this is the only way we who today are privilaged can explore new areas with the citations of the principles used by the former authorities to study new areas of technology and the internet, innovations and industry , business and commerce, communication and the entertainment industries etc. we are responsible today for tomorrows schools. thanks

Interesting what you say about a single psychological theory being too vague. Albert Ellis built on Adler's theroy and developed REBT. As well as providing a rationale for the cognitive aspect of psychology - activating thought, emotion as energiser of action, Adler wrote about the holistic aspects of his theory as early as 1912. Ansbacher and Ansbacher acknowledged that and translated this quote from him: "Sometimes the mouth lies and the mind does not understand, but the functions of the body always speak the truth" Adler 1956, p. 434. He valued metaphor as the generator of information about personality beliefs discovered through early recollections and dreams. He developed a remarkably comprehensive theory.

I believe that all of the key psychological perspectives have their merits but to ask which one is the foundation is a very interesting question. Are we trying to explain the drivers and barriers precipitating behaviour or does a foundational theory dig deeper into the subtler aspects and influences? As far as explanatory power goes, I generally look to evolutionary psychology as a foundation upon which the others build but I feel that is even limited to explanations based on a more primal world in which we no longer live. As such our psychology is adapting rapidly. Treatment foundation is an even more fraught question which I would not dare attempt to answer.