From a highly realised ex-moderator, Namelessness (he no longer
posts in this forum) explaining a quintessential part of the
Platform Sutra:
No thought, no form and no attachment is the quintessence of the
Sutra. But it is not annihilation. It means to be detached from all
thought, form and attachment.
Good Friends, to keep our mind free from defilement
under all circumstances is called 'No Thought'. Our mind should
stand aloof from circumstances, and allow no reaction to our mind
from circumstances. But
it is a great mistake to suppress our mind from all thinking; for
even if we succeed in getting rid of all thoughts, and die
immediately thereafter, still we shall be reincarnated
elsewhere. Mark this, treaders of the Path. It
is bad enough for a man to commit blunders from not knowing the
meaning of the Dharma, but how much worse would it be to encourage
others to follow suit? Being deluded, he sees not and in addition
he blasphemes the Buddhist Canon. Therefore 'No Thought' is taken
as the object.
Good Friends, let me explain more fully why we take 'No Thought' as
our object. It is because there is a type of man under delusion who
boasts of the realization of the Self-nature; but being carried
away by circumstances, ideas rise in his mind, followed by
erroneous views that are the source of all sorts of false notions
and defilements. In the Self-nature, there is intrinsically nothing
to be attained. To say that there is attainment, and to talk
thoughtlessly on merits or demerits are erroneous views and
defilements. For this reason we take 'No Thought' as the object of
our School.
Good Friends, what is that should be 'No'? What is that should be
'Thought'? 'No' means to have no dualistic and
all defiling conceptions. 'Thought' means to fix our mind on the
true nature of Tathata, for Tathata is the quintessence of thought,
and thought is the result of the activity of
Tathata. It is the positive essence of Tathata
- not the sense organs - which gives rise to 'thought'. Tathata
bears its own attribute, and therefore it can give rise to
'thought'. Without Tathata the sense organs and the sense objects
would perish immediately.
Good Friends, because it is the attribute of Tathata which gives
rise to 'thought', our sense organs - in spite of their functioning
in seeing, hearing, touching, knowing, etc. - need not be tainted
or defiled in all circumstances, and our true nature may be
'self-manifested' all the time. Therefore the Sutra says,
"Even all Dharmas can be easily
distinguished, the 'First Principle' is still
immovable"
Here the patriarch taught us how to be away from our thought.
This is difficult because it will take us many years to practice
that. But after that, our thoughts would be vanished naturally.
Thats how No thought can be accomplished. So it is not wise to
suppress our mind from thinking, for whatever is suppressed will
definitely strike back.
We still need to distinquish things in order to survive. The key to
non-duality is to find our inner An-Hsiang first, and let An-Hsiang
be the only response we have to all circumstances. 
