One verse

Srimad Bhagavatam 4.22.31

4.22.31

भ्रश्यत्यनुस्मृतिश्चित्तं ज्ञानभ्रंश: स्मृतिक्षये । तद्रोधं कवय: प्राहुरात्मापह्नवमात्मन: ॥ ३१ ॥

bhrasyaty anusmrtis cittam jnana-bhramsah smrti-ksaye tad-rodham kavayah prahur atmapahnavam atmanah

bhrasyati
becomes destroyed
anusmrtih
constantly thinking
cittam
consciousness
jnana-bhramsah
bereft of real knowledge
smrti-ksaye
by destruction of remembrance
tat-rodham
choking that process
kavayah
great learned scholars
prahuh
have opined
atma
of the soul
apahnavam
destruction
atmanah
of the soul.

When one deviates from his original consciousness, he loses the capacity to remember his previous position or recognize his present one. When remembrance is lost, all knowledge acquired is based on a false foundation. When this occurs, learned scholars consider that the soul is lost.