Chandogya Upanishad is one of the oldest Upanishads written on the Vedic Brahmana period about ninth to eighth century BC. Chandogya Upanishad is associated with Sama Veda. It is the part of Chandogya Brahaman that contains ten chapters. The 12th Khanda of Chapter Seven of Chandogya Upanishad states about the incorporeal Self. Prajapati here explains Lord Indra that the body is immortal and is prone to death. The Self that resides within it is immortal and incorporeal. This embodied self is subject to pain and pleasure. Thus, till a person is identified with the body he cannot escape the feelings of pain and pleasure. However, if one separates himself from the body then he does not need to face any emotions.
Prajapati further explains Lord Indra that the wind, cloud, lightning and thunder are without body. All these arise from the akasa and attain the highest light and they all appear in their own forms. Even man that arises from the body, reaches the highest light, and appears in his own form. He is stated as the highest person in that form. He then laughs, plays, rejoices with all without thinking of the body with which he was born. Just like an animals remains attached to the cart, the Prana also remains attached to the body. When a person in the eye dwells in the body, he stays where the organ of sight has gone into the akasa. It is the pupil of the eye. The eye serves as the source of seeing. One who thinks of smelling is the Self. Here the nose serves as the source of smelling. One who thinks of speaking is the Self. The tongue is the source of speaking. He who thinks of hearing is the Self. Here the ear is the source of hearing. He who thinks that he must think is the Self. Here the mind is the divine eye. The Self can see all the desires in the Brahmaloka with its divine eyes. Thus, the Self should be meditated upon. The gods also meditate on the Self hence all the worlds and desires belong to them. He who knows that and realises the real Self understands and obtains all worlds and all desires.
