The DNA of Personality

Acarkan sets up the book's central metaphor in the preface: just as DNA is our body's biological programme, our psyche has an innate «operating system», and that is temperament. Siblings raised in the same family and culture yet with different personalities are the proof. The author rejects gender, parents, education and culture as the basic determinants of personality. The book opens with broad promises: self-knowledge, understanding others, empathy and better relationships.

Part one sets the tone: the human being is a «bio-psycho-spiritual» entity with the spiritual level at the top. At that level there is no conflict, lack or unease; from this the author concludes that «the concept of mental disorder and illness is wrong» — the spirit cannot fall ill, problems arise only at the level of the self (nafs). References come from Shankara, the Islamic distinction between practical and transcendent intellect, and Socratic anamnesis. At the psychic level there are three centres: an action centre oriented to protecting existence, a desire-feeling centre seeking relationship and recognition, and a thinking centre seeking knowledge and security.

The most questionable part is the Q&A in Part IV. According to the author, temperament is innate, can be «fully and clearly» diagnosed «even within the first year» and never changes; what changes is only movement between healthy, average and unhealthy levels. The book also notes that no regular link has been found between parents' and children's types. To «isn't this labelling?» the answer is that classifying animals as vertebrate or invertebrate isn't labelling, and neither is this. The analogy doesn't persuade, since biological classification rests on measurable facts.

On the model's origins, Acarkan writes that it rests on three faculties found in Aristotle and Islamic-Eastern thought, and reached a wide audience in the second half of the 20th century through Oscar Ichazo and psychiatrist Claudio Naranjo. The book lists researchers who built measurement tools and says the model is used at universities such as Georgetown and Stanford, but gives no concrete sources for these claims. The Enneagram's validity in scientific research is disputed, and the book engages with none of these criticisms.

The type portraits are the book's real strength. «Ones» — «the type seeking right action and perfection» — are described under core search, secondary searches, characteristic attitudes, strengths and risks. Their tendency to become conservatives when they find the status quo ideal and reformers when they find it wrong, to spot and correct errors quickly, and to criticise themselves before others is vividly drawn. Each type also comes with healthy, average and unhealthy levels, which guards the reader against hasty judgements.

The style is plain but repetitive: the same ideas are restated several times, and the text has a fair number of typos. Overall, the book is a broad resource for Enneagram fans; readers approaching it as psychology should treat its claims with caution.

• Detailed portraits built on the same template for each type
• Separation of healthy, average and unhealthy levels
• An appendix comparing the model with personality theories