In the context of the Three Turnings of the Wheel of Dharma, the First Wheel teaches emptiness indirectly and the latter two directly. That is to say, the First Dharma Wheel covers the vehicles of shravakas and pratyekabuddhas, as well as the philosophical schools of Vaibhashika and Sautrantika, while the Middle and Final Dharma Wheels cover the vehicle of bodhisattvas as well as the philosophical schools of Mind Only and the Middle Way. Adding these earlier and later schools together, they are known as the Four Philosophical Schools.
First, the basic position of the Vaibhashika School is that existence is the five aggregates and that the articles of existence are four: dwelling place, food, clothing, and medicine. They regard the noble potential as being the mental state of contentment that is detached from existence and the articles of existence.
Second, the proponents of Sautrantika regard the noble potential as being a mental seed, the potential for undefiled wisdom to arise.
Third, the Mind Only followers regard the noble potential to be a potential for developing the undefiled qualities, which is present in one’s mental continuum since the beginning and which is a natural possession.
These three schools are systems that regard the sugata essence as being a conditioned phenomenon and are therefore known as systems that are Proponents of Concrete Existence.
Fourth, the followers of the Middle Way are for the most part alike in regarding the suchness as being endowed with impurity, although there are indeed many different ways in which they define that. Here, according to the uncommon Mahayana system, the mind-essence that is naturally pure since the beginning, the all-pervasive essence that is unobstructed emptiness and cognizance, the nature that is present without change or alteration, is called sugata essence in all the sutras of definitive meaning. The Uttaratantra says further:
Because the body of complete buddhahood is all-pervasive,
Because the suchness is indivisible,
And because of possessing the potential,
All beings constantly have the buddha essence.
By means of these three reasons, Maitreya taught that all sentient beings possess the sugata essence and furthermore established that through nine analogies with nine meanings. The nine analogies are, from the same text:
Like a buddha statue within a lotus, honey in a beehive,
A kernel within a husk, gold within filth,
A treasure in the ground, the fruit of a bamboo shoot,
A buddha image within tattered rags,
A king in the womb of an inferior woman,
A precious image covered in earth;
Similarly this potential is present within all beings
Who are obscured by the temporary stains of disturbing emotions.
The same text states further:
The meaning of this ultimate dharmadhatu space should be known
Through its essence, cause, result, function, endowments,
Its approach, phases, and all-pervasiveness,
And that it is forever unchanging and never separated from its qualities.
This has been extensively explained by the ten presentations of the intended meaning of the sutras.
At the time of the First Dharma Wheel, the seed of the Second Dharma Wheel is present by stating simply the word “unconstructed” such as in the verse:312
I have found a nectarlike truth,
Profound, tranquil, unconstructed, luminous, and unconditioned,
But whomever I teach, there is no one who will understand,
So I shall remain silent in the forest.
At the Second Turning of the Wheel of Dharma, numerous seeds of the Final Dharma Wheel are present through such statements as:
Mind is devoid of mind because the nature of mind is luminous.313
and,
It is not empty, it is not not empty, [and so forth].
The Final Turning of the Wheel of Dharma explains with great clarity the entire meaning taught in the Unexcelled Tantras of Mantrayana, using such words as pure, crystal clear and luminous, or sublime purity, bliss, identity, and permanence.
The term “sugata essence” applies to the fact that the essence mind, which is present as the indivisibility of the [two] truths, is itself the identity of buddhahood. The term “naturally present potential” applies to the essence of mind, which is present as the unobstructed potential for the qualities of dharmakaya arising from its empty aspect and the qualities of rupakaya arising from its manifest aspect. It is also called “all-ground wisdom” because of being the ground from which both samsara and nirvana arise, and it is called “defiled suchness” because of being linked to defilement while in the state of a sentient being.
The Three Stages further explains:
It is called “ground” because without exception it is the source
Of all phenomena of the two denominations.314
The Sutra of the Dense Array states:
The stainless all-ground will through merit
Turn into the tathagata.
The Scripture of the Compendium of Knowledge says:
It is courageous as it is the all-ground, the space of all.
The vajra essence is extremely courageous.
Courageous mind is the space of all buddhas.
The courageous vajra mind is suchness.315
Furthermore, the Uttaratantra states:
This potential is devoid of the temporary [defilements]
Which bear the mark of being discardable.
But it is not empty of the unsurpassable qualities,
Which bear the mark of being intrinsic.