I wasn't making a philosophical but a practical observation. Nevertheless, if you think it's appropriate here to bring that up, there it is:
in the ultimate sense all the truths should be understood as void because of the absence of (i) any experiencer, (ii) any doer, (iii) anyone who is extinguished, and (iv) any goer. Hence this is said:
'For there is suffering, but none who suffers;
Doing exists although there is no doer;
Extinction is but no extinguished person;
Although there is a path, there is no goer'.
(Vsm. XVI. 90.)
That which is an agent
Does not perform an existent action.
Nor does that which is not an agent
Perform some nonexistent action.
But the next chapted of the MMK deals better with the "Witness" idea, examining the concept of a perceiver behind things perceived.
That's going into emptiness and the ultimate truth. Ultimately there is no action to speak of either, so we also have no basis for which an agent could exist.
However, in the realm of cause and effect, or conventional truth, there are agents of actions. If there were not agents of actions, we would fall into determinism where sentient beings would have no control over their actions and vimukti
or liberation would be a matter of random chance.
In terms of practice, it is possible to separate objects from the subject. "I'm watching the thoughts." Then should come the turning of attention from thoughts to the watcher. Is there really something/someone watching? No. There is no witness, no self, anatma. Are there thoughts? Yes. Is there a thinker? No.
There must be, conventionally speaking at least, a kartṛ
(agent) for karma
(action). This kartṛ
need not be atman
. Just as sentient beings are so described we can also say a kartṛ
is dependently originated ergo anātman
and empty of any self-existence or svabhava
There may not be an absolute self, but there is a person
or agent that is neither apart from the aggregates nor is any or all of the aggregates. Ignorance or avidyā
leads to the appearance of an illusory agent, which while illusory still commands causal efficacy. A person is illusory, yet it still does arise from the perspective of an ignorant being
It is thus that the Treatise on Buddha Nature states the following (my translation below):
《佛性論》卷2〈2 三性品〉：「分別性實相者。人法增益及損減。由解此性故。此執不生。是分別相人法者。是分別所作。若依真諦觀。此人法為有名增益執。若依俗諦觀。此人法是無名損減執。若通達此分別性。則增益減損二執不生。」(CBETA, T31, no. 1610, p. 794, c17-22)
or the discriminating nature's true quality (tattvasya-lakṣaṇam
) is the reification (samāropa
) and elimination (apavāda
) of person and phenomenon. Having comprehended this nature, these attachments thus do not arise. This discrimination characteristic, person and phenomenon are created by discrimination. If we rely on the view of the ultimate truth (paramârtha-satya
), the person and phenomenon are [seen as provisionally] existent and [this is] called the attachment of reification (samāropa
). If we rely on the conventional truth (saṃvṛti-satya
), the person and phenomenon are [seen as] non-existent and [this is] called the attachment of elimination (apavāda
). If we completely understand this discriminating nature, then the two attachments of reification and elimination do not arise."
In short, as long as one has not comprehended parikalpita-svabhāva
, the appearance of a person or agent, whether it be of a reified type or posited as non-existent, will occur. Basically, if one completely realizes parikalpita-svabhāva
or the discriminating nature, there is neither phenomenon nor person.
To reiterate, you said:
Are there thoughts? Yes. Is there a thinker? No.
There are both thoughts and thinkers to the ignorant being. However, if realization occurs, there is neither thought nor thinker.