Is the Mind (Citta) the Self? If not, what is it? It's been discussed in all perspectives that the Buddha was teaching about not-Self (Anatta) in this forum. However, it taught that one should empty the Mind (Citta) to realize Anatta, or Sunyata, in Dhyana (Jhana). If this mind is already not-Self, why it needs to be emptied and what is to be emptied? If this mind is also not-Self, how does it have the autonomy/independence to realize/discern Emptiness? If this mind is Self, how can it realize not-Self? If this mind is not-Self, who controls/owns the Five Aggregations and intellect? Who/what is this mind?
1. If this mind is already not-Self, why it needs to be emptied and what is to be emptied?


The mind is only 'not-self' from the viewpoint of enlightenment &amp; truth. But for the unenlightened mind, the mind is 'self' because of ignorance ('blindness'). 

The mind is ideally 'emptied' so it can see clearly, similar to cleaning a window or mirror. It is emptied of the pollutants that obscure clear seeing, similar to a window or mirror cleaned from dust. 

The Pali scriptures describe this in the Sangaravo Sutta.


  Imagine, Brahman, a bowl of water mixed with lac, turmeric, dark green or crimson dye. If a man with good eyesight were to look at the
  reflection of his own face in it, he would not know or see it as it
  really was. In the same way, Brahman, when a man dwells with his heart
  possessed and overwhelmed by sense-desires... then he cannot know or
  see, as it really is, what is to his own profit, to the profit of
  others, to the profit of both. Then even sacred words he has long
  studied are not clear to him, not to mention those he has not
  studied. Sangaravo Sutta







  2. If this mind is also not-Self, how does it have the autonomy/independence to realize/discern Emptiness?


The mind has a wisdom faculty to discern emptiness. It is not possible to explain how or why this can occur. The Pali suttas simply say:


  Discernment (wisdom/panna) &amp; consciousness are conjoined, not disjoined. It's not possible, having separated them one from the
  other, to delineate the difference between them. For what one
  discerns, that one cognizes. What one cognizes, that one discerns.
  Mahavedalla Sutta


Jesus Christ said: 


  If the flesh came into being because of spirit (consciousness), that is a wonder. But if spirit came into being because of the body, that is the wonder of
  wonders. Yet I marvel at how this great wealth has come to dwell in
  this poverty.
  
  Gospel of Thomas







  3. If this mind is Self, how can it realize not-Self?


The citta is not a self. It is impermanent. It is not-self. To quote: 


  "All things are not-self". Dhammapada 279.
  
  
  
  It would be better for the uninstructed run-of-the-mill person to hold to the body composed of the four great elements, rather than the
  mind, as the self. Why is that? Because this body composed of the four
  great elements is seen standing for a year, two years, three, four,
  five, ten, twenty, thirty, forty, fifty, a hundred years or more. But
  what's called 'mind (citta),' 'intellect (mano)' or 'consciousness' (vinanna) by day and by
  night arises as one thing and ceases as another. Assutavā Sutta







  4. If this mind is not-Self, who controls/owns the Five Aggregations and intellect? Who/what is this mind?


Nothing owns or ultimately controls the five aggregates, as was explained at the start of the Buddha's 2nd sermon. However, the mind itself, via enlightenment, can control its mental formations (sankhara) while the mind is alive. 

SN 12.12 states there is no "who" that is conscious. The idea of "who" arises later at clinging &amp; "becoming":


  "Who, O Lord, has a sense-impression?"
  
  "The question is not correct," said the Exalted One.
  
  "I do not say that 'he has a sense-impression.'...the correct way to ask the question will be 'What is the condition of sense-impression?'
  And to that the correct reply is: 'The sixfold sense-base is a
  condition of sense-impression, and sense-impression is the condition
  of feeling.'"
  
  "Who, O Lord, feels?"
  
  "The question is not correct," said the Exalted One....the correct way to ask the question will be 'What is the condition of feeling?'
  And to that the correct reply is: 'sense-impression is the condition
  of feeling; and feeling is the condition of craving.'"
  
  "Who, O Lord, craves?"
  
  "The question is not correct," said the Exalted One. "I do not say that 'he craves.'...the correct way to ask the question will be 'What
  is the condition of craving?' And to that the correct reply is:
  'Feeling is the condition of craving, and craving is the condition of
  clinging.'"
  
  "Who, O Lord, clings?"
  
  "The question is not correct," said the Exalted One, "I do not say that 'he clings.' Had I said so, then the question 'Who clings?' would
  be appropriate. But since I did not speak thus, the correct way to ask
  the question will be 'What is the condition of clinging?' And to that
  the correct reply is: 'Craving is the condition of clinging; and
  clinging is the condition of the process of becoming.' Such is the
  origin of this entire mass of suffering.


As previously said, the mental faculties are named according to their functions: 


  And why, bhikkhus, do you call it feeling? ‘It feels,’ bhikkhus, therefore it is called feeling.
  
  And why, bhikkhus, do you call it perception? ‘It perceives,’ bhikkhus,therefore it is called perception.
  
  And why, bhikkhus, do you call it formation/construct? ‘They construct the constructions,’ bhikkhus, therefore they are called
  formations.
  
  And why, bhikkhus, do you call it consciousness? ‘It cognizes, ’ bhikkhus, therefore it is called consciousness.
  
  SN 22.79