Satya Sodhana in Hinduism is the search for god, the ultimate truth. All the qualities of the Ultimate Truth are the qualities of God. In Hindu philosophy, God is the Ultimate Truth. Satya Sodhana is nothing but a search for the Supreme. It is not simple, and requires great sadhana or tapasya. One need not wander about here and there to find the Absolute; He is within oneself. As being itself is the Absolute (aham brahmasmi), one should search for Truth within oneself.
According to Vedas and Upanishads, the following are the qualities of Truth:
Ultimate truth is the divine principle, which always exists. Permanent and immortal existence is the most important quality of Truth, and this quality is unquestionably applicable to the Supreme. Hence the Supreme is the Ultimate Truth, which always exists and does not change according to place, time and condition.
Ultimate Truth is imperishable and therefore immortal. Sat is another name of satya. The whole world is divided between sat and asat, that is truth and untruth. A man who possesses the power to distinguish between sat and asta is supposed to know satya. Satya-viveka (distinction between what is sat and what is asat with the help of reason), and the knowledge that maya or matter (material world which reveals the qualities of sattva, rajas and tamas) is perishable, reveals the nature of maya as asat and the imperishable as sat or the Truth.
Satya is not a passive principle but is a force full of chetana (consciousness). The atma (self) is chetana and every living animal has it. The Supreme is reflected in chetana. We can perceive the Supreme in the form of atma in every living being. Atma is immortal and leaves the body at the time of death, but it never dies – like the Ultimate Truth, Death means permanent parting of atma from the body.
The Ultimate Truth or the Supreme always gives us joy which is spiritual or divine. It is permanent and never stales.