When we examine the works of Sankara, however, we find a very sparing use of
the word samadhi. In the Brahmasutrabhasya he makes three references to samadhi
as a condition of absorption or enstasis. In the first (2.1.9) , he implicitly
refutes the idea that samadhi is, of itself, the means for liberation, for he
says:
Though there is the natural eradication of difference in deep sleep and in
samadhi etc., because false knowledge has not been removed, differences occur
once again upon waking just like before.
What Sankara says is that duality, such as the fundamental distinction between
subject and object, is obliterated in deep sleep and in samadhi, as well as in
other conditions such as fainting, but duality is only temporarily obliterated
for it reappears when one awakes from sleep or regains consciousness after
fainting, and it also reappears when the yogin arises from samadhi. The reason
why duality persists is because false knowledge (mithyajana) has not been
removed. It is evident from this brief statement that Sankara does not consider
the attainment of samadhi to be a sufficient cause to eradicate false
knowledge, and, according to Sankara, since false knowledge is the cause of
bondage, samadhi cannot therefore be the cause of liberation.
The Question of the Importance of Samadhi in Modern and Classical Advaita
Vedanta By Michael Comans, Ph.D.