Aparokshanubhuti is a text credited to Adi Shankaracharya
Just as light is required to see an object; one attains
knowledge only through the means of enquiry.
The self alone is permanent; all that is seen here is transient
– such a settled conviction is truly known as discrimination.
Concentration of the mind on the one Reality [Brahman] is
regarded as Samadhana.
Who am I? How is this world created? Who is its creator? Of
what material is this world made? This is the way of that enquiry. I am neither
the body, a combination of the five elements of matter, nor am I an aggregate
of the senses; I am something different from these. This is the way of that
enquiry.