Katha Upanishad Verse 2.2.5

This verse clarifies that the biological functions of prāṇa (incoming breath) and apāna (outgoing breath) are not the primary cause of life. While these vital breaths are necessary for the body’s survival, they themselves depend on a higher, underlying principle—the Atman. It is this “other” essence, the Self, that truly sustains and animates all mortal beings.

Sanskrit Verse

न प्राणेन नापानेन मर्त्यो जीवति कश्चन । इतरेण तु जीवन्ति यस्मिन्नेतावुपाश्रितौ ॥ ५ ॥

Transliteration

na prāṇena nāpānena martyo jīvati kaścana | itareṇa tu jīvanti yasminnetāvupāśritau || 5 ||

Translation

Not by prana, not by apana, does any mortal live; but it is by some other on which these two depend that men live.