Let me further add some material that might be useful regarding the first outlined cause.
The essay below was written by Chéngguān (738-839CE). He provides an analysis of the emptiness of the person followed by an examination of the pañca-skandhāḥ (emptiness of dharma). Chéngguān was an eminent monk of the Huáyán school of Buddhism during the Tang Dynasty (618-907CE). He was an erudite scholar composing over thirty works on a variety of subjects.
Examination of the Five Aggregates
Written by Śramaṇa Chéngguān
It is asked, “A common person seeks liberation. How should he practise?”
We respond saying that one should practise the two examinations.
What are the two examinations? The first is the examination of the emptiness of persons. The second is the examination of the emptiness of phenomena (dharma).
The root of birth and death – nothing goes beyond the two attachments of persons and phenomena.
One misunderstands the body and mind's characteristic of totality and thus grasps the self of the person as an actual existent.
One misunderstands the five aggregates' individual characteristics and thus conceives the self of a phenomenon as an actual existent.
For the conception of the self of person we utilize the first examination and investigate it.
We then know the five aggregates come together and are provisionally called a person.
Each are carefully examined. We only see the five aggregates. We seek out the self-characteristic of the person and in the end it cannot be found.
What are called the five aggregates? They are form (rūpa), feeling (vedanā), perception (saṃjñā), volitional formations (saṃskāra) and consciousness (vijñāna).
How does one examine them?
The body is the aggregate of form. This is said to be earth, water, fire and wind. What are their characteristics?
Solidity is earth. Moistness is water. Warmth is fire. Movement is wind.
In examining the mind there are four aggregates. These are said to be feeling, perception, volitional formations and consciousness. What are their characteristics?
Sensation is feeling. Apprehending characteristics is perception. Creating actions is volitional formations. Cognition is consciousness.
If we can, based on these characteristics of body and mind, carefully examine and see clearly, then in all places we only see the five aggregates. We search out the self-characteristic of the person and in the end it cannot be found.
We call this the examination of the emptiness of persons. If one utilizes this examination then one departs birth and death within the six realms and forever abides in nirvāṇa. We call this the liberation of the two vehicles.
For the conception of the self of a phenomenon we utilize the later examination and investigate it. We then know that each of the aggregates all arise from conditions and all are without self-essence. We seek out the characteristics of the aggregates and they cannot be found and so the five aggregates are all empty.
We call this the examination of the emptiness of phenomena. If we investigate with both examinations we understand the person's self and the phenomenon's self – ultimately empty without existence.
Free from all fears, crossing over all pains and emerging into existence as a Bodhisattva – we call this ultimate liberation.
It is asked, “Seeking liberation is only just understanding delusion and realizing the truth. It is merely being able to realize the principle of tathātā – in quietude without thoughts and then binds are removed. How does one provisionally arouse the mind, examine the aggregates and then seek liberation? Is this not in opposition to the principle?”
We answer: with what do you stand without aggregates, truth and delusion? For the moment the five aggregates are a different name for the body and mind. Supposing the practitioner is not aware of the truth and delusions of body and mind, how could they completely understand them?
They do not reach the source of truth and delusion and practises are vainly undertaken.
Thus the scripture states, “It is like in emptiness ultimately nothing being able to be established.”
This is how it is said. The provisional conception of the self of the person is an attachment of the ordinary person. The conception of the self of a phenomenon is the hindrance of the two vehicles.
Thus we have them practice the two examinations and then they are able to understand delusion and realize the truth. How could you do without this?