These first three purusārtha are the scope for Karma kanda (first part of Veda), where prayer, ritual, reaching out activities are taught. These three together called Preyas pleasant experiences. But there are limitation of Preyas:
1. Anityam - impermanent. The result of any of these three pursue are impermanent, because any action with its accessories all are impermanent. Impermanent means can not get permanent result.
2. Dukhamisrīta - fraud with pain. There is pain while pursuing it, pain while couldn't maintain it (after being obtained), and pain while loosing it.
3. Atrptikah - never gives full satisfaction.
4. Bandhakatvam - create dependent.
Therefore there is the forth purusārtha, which is Moksa purusārtha the pursue of freedom from bondage, which is the cope for Jñāna Kanda (last portion of Veda). What is bondage? Bondage is the situation we found yourself with and we are not comfortable with, but we can not get ourself out of it. And this bondage is differ from people to people. Some people want to get get married, to released from the bondage of bachelorhood, and some married people want to get out of the married bondage. Some people want to get a job to released from the bondage of joblessness, and some others want to released from the bondage of work. No matter what kind of means we employ to released from the bondage, they don't give us liberation. It just bring us jump from one bondage to another bondage. This is life of samsara. The life of becoming.
From one situation, one is seeking for another situation. Every seeking itself is a bondage. When one seeking security as the means to of life in the form of wealth or relationship, one become bound by them. When one seeking enjoyments as their goal of life, one become bound by them. When one seeking to be a dharmika person for the better lot of life in heaven, one become bound by it. Every seeking actually is a seeking of liberation. Because liberation is putting an end to the problem it self. When one seeking wealth for security, actually they are seeking liberation from poverty. When one seeking for enjoyment of eating, because one wants to putting an end to the craving. When one seeking for better lot in heaven, because one wants to put an end on the unfavourable situation here in this life. Therefore moksa purusārtha underlying other three.
Therefore moksa can be said as the sense of wholeness / happiness which not depend on arriving or departure of any object and situation.
Liberation essentially is putting an end to all problems by the knowledge of the truth of the problem. This knowledge is knowledge of oneself, which is unfold by the teaching of Upanishads, also known as Vedānta. All the upanishads only having one purport to reveal the truth Tat Tvam Asi, you are that wholeness.
When we say this text is explaining the idea of Vedānta teaching, we should know first what is Vedānta. The scriptures of Hindu are called Vedās which consist of two parts, namely Karma Kāndah which is dealing with the theological concept of God and Heaven like others religion, including rituals, mantras, dharma do and don't. And second part is called Jnāna Kanda consists of Upanisads which is imparting the knowledge of the non dual limitless reality.
Why we choose Tattvabodhah as the text to start with? First is to have a systematic learning for self knowledge. Second is to introduce the technical terms used in the scripture which is almost impossible to translate in any other language, which helps the students for further study of others scriptural text like Upanisad and Bhagavad Gītā.
Tattvabodhah is written by Ādi Śankarācārya. It is in the tradition for the ācāryas to start their work with a prayer offers to the God or Guru, because of the conduct which always with a prayerful attitude. Besides that, there is always an external factor call Daivam which is not under our control. Therefore the author invokes the grace of the Lord in the very first verse, for the success to complete the text which he has started. In the same manner for us, we are chanting this very first verse sincerely to ask for grace for our completion of the study which we have commenced.
Vāsudevendrayogīndraṁ natvā jñānapradaṁ guruṁ I
Mumukṣūṇāṁ hitārthāya tattvabodho'bhidhīyate II
Having saluted Vasudevendra, the foremost of the yogins, the guru who gives knowledge, Tatvabodhah the knowledge of the truth is presented for the benefit of those desirous of liberation.
This very first verse is called invocatory verse, where ācārya offer the prayer, saluting his Guru Vāsudeva who are looked upon as manifestation of the Lord himself. He is called Vāsudevendrayogīndram because he is a great yogi (the one who has self knowledge). In the same time Vāsudeva also is another name of Lord Krsna. He is the guru, one who shines the light of knowledge to remove the darkness of ignorance. He is the bestower of the self-knowledge.
In this first line, ācārya hinting a very important idea also, which he didn't get this self-knowledge by self-study. Every learning process, we need a teacher. Especially in the knowledge of the self, where the confusion was there since time beginning less. Therefore a teacher who understand this subject matter and follow a tradition of teaching called sampradāya is there to guide us to find the clarity.
In second line, ācārya stated the purpose of the text. He imparted the knowledge of the self for the benefit of the mumuksu (the seeker of freedom).
Now we enter into the first chapter.