Self - the pure mind?

[Nanda Kumar]

The standard Advaitam argument to negate the reality of the body and
mind revolves around the three states - waking, dreaming and dreamless
sleep.

In the waking state the reality of the mind and body are felt.

In the dreaming state the 'I' lacks the body and is felt only at the mind
level.

In the dreamless sleep both the body and mind are not felt.

OK, but who exactly sets the standards for the 'I', body, mind.  For
sometimes even in the dream state the physical body is affected. Why
can't it just be a natural state of the mind to shut down and reawaken
when the body wakes up? Is there any rule which says it should always
be up and running?

In deep sleep even the conciousness is absent. So how can it be
positively said that the Self alone shines during susupti?

Even the shruti says the Self is beyond the reaches of the senses and
the intellect. So in the process, at a mature stage, a mystical Self
overcomes the mind and envelopes the being, might be true, but can only
be certified or claimed by 'experienced' beings. Whether it's just a
modification or altered state of the mental process itself cannot be totally
proved.