This book deals with the operations of the mind, citta, and its accompanying mental factors, cetasikas. A detailed study of the many types of cetasikas will help the reader to know his own defilements and to develop good qualities and eventually, to eradicate all defilements. Defilements and good qualities are different types of cetasika. In this study I refer to my book Abhidhamma in Daily Life which deals with the basic points of the Abhidhamma. It is useful to read this book first in order to understand my study on cetasikas. 

     The reader may wonder what the purpose is of the many Pali terms used in this book. In the course of his study he will see that the Pali terms are helpful for precision of understanding. I have used the Pali terms next to their English equivalents but  the English terms often have a specific meaning in the context of Western psychology or philosophy. We should try to understand the correct meaning rendered by the Pali terms. 

     In this study on cetasikas I have quoted from the first book of the Abhidhamma, the Dhammasangani ( Buddhist Psychological Ethics ). I also used Buddhaghosa's commentary to this book, the Atthasalini ( in English: The Expositor ) and his encyclopedia on Buddhism, the Visuddhimagga ( in English : The Path of Purification ).

     Buddhaghosa's commentaries date from the fifth century A.D. He edited in Sri Lanka old commentary works with utmost conscientiousness and translated them from Singhalese into Pali. The reader will be impressed by the discriminative, refined knowledge of all the details of the Buddha's teachings and by the vivid way he illustrates points of the teachings with examples. He continuously points to the goal: the development of insight in order to see realities as they are. I quoted from the suttas texts which deal with the development of all kinds of kusala, comprising the development of calm and the development of insight. These texts can encourage us to keep in mind the purpose of our study. Some people believe that the Abhidhamma, the teaching on ultimate realities, is not the original teaching of the Buddha. The Buddhist scriptures, the Tipitaka, consist of the Vinaya (book of Discipline for the monks), the Suttanta  discourses) and the Abhidhamma. The Abhidhamma enumerates all realities and the different conditions for the phenomena which arise. In order to show that the different parts of the scriptures are one, that they are the Buddha's teaching, I quoted also from the suttas texts which deal with ultimate realities. There is also Abhidhamma in the suttas. In the suttas we read time and again that the Buddha spoke about ultimate realities appearing through the senses and through the mind-door. In order to understand the suttas some basic knowledge of the Abhidhamma is indispensable. As we study the Abhidhamma we will become more convinced that the Abhidhamma
pertains to our daily life, that it teaches about the phenomena we can experience at this moment. As we continue with the study of the Abhidhamma we will be impressed by the depth of its teaching. No ordinary person could conceive such a detailed exposition of everything which is real, except an Enlightened One. The reader may find this book technical, but as he proceeds he will find that a detailed study of realities helps him to understand his daily life.

     I wish to express my deepest thankfulness to Ms. Sujin Boriharnwanaket in Bangkok, who greatly assisted me in understanding the Dhamma and its application in daily life. I based my study of cetasikas on the lectures she held in the Saket Temple in Bangkok. I also wish to express my appreciation to the "Dhamma Study and Propagation Foundation" ; to the sponsors of the printing of this edition, Asoka Jayasundera and family, Anura Perera and family and Laksham Perera and family; and to the publisher Alan Weller. With their help the publication of this book was possible. All the texts from which I quoted have been printed by the PaIi text Society1.

     I will now continue with a general introduction in order to help the reader to have more understanding of the nature of the cetasikas which accompany the different types of cittas.

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