The great sage Patanjali in his work Yogasutra codified all yogic knowledge and practices which prevailed in ancient India in the form of aphorisms. He defined Yoga in a simple way as - controlling of thoughts arising in the mind(I.2). The nature or work of mind is to think or desire always. As waves are generated along the seashore, so thoughts are generated in the mind incessantly. In order to fulfill these desires man acts relentlessly. When thoughts are controlled or prevented, the outwardly moving mind turns inwards. The sphere of the activities of mind contracts and mind comes to the center. At the center of mind lies the true self or soul(atman).

True self or soul is the source of life and consciousness in all living beings. In fact soul, life and consciousness are one and the same and constitute the only truth in the whole universe. The Upanishads which contain the spiritual cream of Indian Philosophy, describe that soul(atman) is Brahman, the ultimate Reality. World is not different from being, being is not different from Atman and Atman is not different from Brahman.

When thoughts in the mind are controlled, Yogasutra describes - the the seer rests in his true self(I.3). When all thoughts cease to exist, mind becomes pure conscious. As water is purified through filtration, so mind is purified by controlling thoughts. The pure conscious mind is the true self of a being. So through the practice of Yoga one regains one's true self and nothing else.

Everything has a true self or true nature. The nature of sugar is to give sweetness, the nature of water is to give coolness and the nature of fire is to give heat. When a piece of gold is purified bu burning, it does not change over to any other thing, but becomes pure gold. Only a pure gold is appreciated and is more valuable. Similarly when the mind attains purity, it does not change over to any other thing or merge with something. When mind is pure conscious, it is pure bliss. The real nature of a being is its blissful state. In order to achieve this blissful state people of all religions wander here and there in search of God.

Religious people concieve of a God who is a divine being residing in heaven. This concept and imagination is only the reflection of true self. Heaven is the heart of a being and God is the true self. It is the true self or soul that impells an individual to seek for God. After long searches here and there, one returns to one's true self and realises Gog within.

So the aim of Yoga is to realise this true self or God. Such a God is only real and existent. He gives life and consciousness to all beings. All worlds, all beings and all souls are one and the same. This is the ultimate Truth or Reality.