The study of traits psychology and ethics reveal a similarity of their bases about personality. The simplest hypothesis is the derivation of traits theory from ethics. In this article, the basis of traits psychology in ethics is analyzed. In this way, the approach of traits in personality is studied. Then, the most important ethical theories such as Plato’s, Aristotle’s, Avicenna’s, Feiz Kashani’s, Naraghi’s, Ghazali’s and others’ are discussed. The observations show that explanation of personality based on traits has been a dominant approach in the field of ethics, for many years. Especially, considerable conversion and similarity exists between the traits theory and Ghazali’s view. The research findings show that Ghazali’s approach to personality description and people’s categorization has been based on a simple subjective analysis. Thus, it can be said that eventhough traits psychology has been popular in 1940’s to 70’s with the works of Allport and Cattel, but the basis of traits analysis returns to ethical scholars such as Plato, Aristotle, Avicenna, Ibn Moskevayh, Naraghi and Ghazali
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