KathaUpanishad

yaḥ = who
iha nāna iva paśyati = who sees seperativeness here
mṛtyoḥ mṛtyuṁ gacchati = goes from death to death.
'Even by the mind this (Brahman) is to be obtained, and then there is no difference
whatsoever. He goes from death to death who sees any difference here.'
sarva-bhūtastham ātmānaṁ sarva-bhūtāni cātmani |
īkṣate yoga-yuktātmā sarvatra sama-darśanaḥ ||
Gita 6.29. With the mind harmonised by Yoga one sees equality everywhere;one sees one's
Self as abiding in all beings and all beings in one's own Self.
aṅgu̍ ṣṭha-mātraḥ pu̱ ruṣo̍ madhya̱ ātma̍ni tiṣṭhati |
ī̱śāno bhūta̍-bhavya̱sya̱ na̱ tato viju̍ gupsate | e̱ tad vai tat || 12 ||
puruṣaḥ = The Person
aṅguṣṭha-mātraḥ = the size of a thumb
tiṣṭhati = exists, resides;
madhya ātmani = in the body
īśāna = the Ruler
bhūta-bhavyasya = of the past and the future
tataḥ = thereafter
na vijugupsate = fears nothing
etat vai tat = this verily is that.
'The person (purusha), of the size of a thumb, exists in the middle of the body, as lord of
the past and the future, and henceforward fears no more. This is that.'
This "being" dwelling inside the heart has been equated with the ‘jiva’ or the ‘self’ which carries
the consciousness and a meta-physical body (prakriti), also termed as the karana sharira. The
karana sharira has most transcendental existence and accumulates the experiences of the
physical, earthly life. This 'jiva' is a spark of divinity, and its place in the body is the heart region.
As per Sri Aurobindo, the angustha purusha is made up of elements of chaitya (chetna), i.e. the
angustha purusha is a being existing at the psychic (Chetas) sphere. Sri Aurobindo mentions
that behind the ordinary chakra of the human heart region, inside a deep cave nihite guhayam
as described by the Upanishads, is the center where a divine spark is present. This thumb-sized
purusha is the bird in the twin-bird analogy of the Rigveda and Sankhya (dvau suparna sayuja
sakhaya) which actually gets involved in the prakriti and suffers and/or enjoys the fruits of its
Karma.
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