Ignorant mind and Buddha nature

I have never seen or read any Buddhist teachings that stated or implied that minds were ever in a pure state then became impure. The 3rd Noble Truth states that the mind can be purified and that, once pure or enlightened, never can it become impure again. All Buddhist (and Hindu) teachings that I have ever read (that I can remember) stated that the everyone's continuum has been continuously contaminated (without beginning) So, that clears up your illogical conclusion. Buddhism says the contamination can be cleared then, in the 4th Noble Truth, illustrates the path to clear it.

Buddha-nature in Mahayana literature is quite interesting. (I will let you "google" the term.) The more one understands the concept, I think, the more one understands what one is working "towards". Indeed, the process seems to be more of an "unlearning" process, rather than something one is trying to become. Hope that helps.

It's a Mahayana teaching. Mahayana teaches many things that comply with Taoism but not with the Canon. There is no mention of a ground of being in the Canon, nor of any inherent quality that makes you good or bad either way.

So be advised that if you follow the early teachings, you don't have to writhe around this concept. The Buddha himself, in the entire Pali Canon, never mentioned Buddha Nature.

The seeing of an ignorant mind and buddha nature are dependent of each other. If the ignorant mind is seen, the resulting sufferings, problems, issues of the world, caused by ignorance are spontaneously liberated. Thus the buddha nature depends on having seen that ignorant mind. Since one does have buddha nature from the beginning, ignorance can been seen and sufferings ended. How ignorance came about can be compared with a match starting a forest fire ie, In a blazing forest fire, one does not care about the match that started the fire. The priority is to stop the fire.

Every sentient being has buddha nature, therefore buddha nature is a necessary condition for being a sentient being

1. The traditional presentation is not that our minds used to be pure. Rather, our mind is defiled from beginningless time. 'Defilements' refer to the two obscurations: (1) afflictive obstructions, impediment to liberation and (2) knowledge obscurations (or 'obstruction to omniscience'), impediment to buddhahood.

Maitreya explains nine types of defilements (the first three being the three poisons, and so forth).

2. From Maitreiya's Great Vehicle Treatise on the Sublime Continuum differentiating the Lineage of the Three Jewels (mahayanottaratantra-ratnagotravibhanga), I know of three illustrations of 'buddha nature'. The one we usually speak of is the second: buddha nature as the suchness of the minds of sentient beings (i.e. non-buddhas), that is also called 'suchness with defilements'.

Suchness with defilement is pure by nature, yet it is 'with defilements'. There is no contradiction. It is because suchness is not the basis [of the quality of] being defiled. Maitreya asserts that buddha nature is 'inconceivable in the sense of being difficult to understand' because of being 'pure [by nature] and yet with defilements'.

3. Very important point: A Buddha does not have buddha nature. This is because buddha nature is the emptiness of the mind of sentient beings (i.e. non-buddhas). The emptiness of the mind of a buddha is suchness without defilements and is called Dharmakāya (or more accurately the 'nature truth body'-part of the Dharmakaya). In other words, Dharmakāya (suchness without defilement) is not Tathāgatagarbha (suchness with defilements, buddha nature).

As the emptiness of a pillar (an instance of emptiness) is not the emptiness of a table, the emptiness of the mind of a sentient being is not the emptiness of the mind of a Buddha. This is because emptiness and its basis are one entity (yet mutually exclusive contradictory). In other words, emptiness is always emptiness of something, and so forth. Thus, there is no way one can accurately say “we are buddhas but we just don't know it”.

4. Buddha nature is called a cause but is not an actual cause. It is called a cause because, if our afflicted minds were not empty of true existence (this emptiness being buddha nature), it would not be subject to purification, change, transformation, could not 'interact' or 'be pervaded' by the deeds of a Buddha, etc. It is not an actual cause because buddha nature is suchness with defilements, and a suchness is permanent, and whatever is permanent is unable to perform a function [of causing anything, etc].

I suggest you studying Maitreiya's 'Sublime Continuum...' which was commented upon by Asanga. Asanga's commentary was also commented by Gyaltsab-je.

The best explanation of this I've seen is in Lamp of Mahamudra by Tsele Natsok Rangdrol.

Basically, if we consider everything at the abstract organizational layer underlying both the mind and the matter, the so called "ground of all" -- we will see that everything is inherently perfect. It is the fundamental "suchness" of things as they are (whether experienced by someone or not). Because the universe is already how it is, for perfectly natural and objective reasons, everything that exists or does not exist exists or does not exist for a reason. In this sense everything is complete, without a flaw. That's Buddha nature.

But part of this Buddha nature is natural tendency of the mind to grasp or cling, or in modern terms, to create flawed static models of reality, that are more like caricatures than models, and then get stuck on them. This gives rise to such natural phenomena as ego, the three poisons, and suffering. These two are part of suchness, and in this sense they are also Buddha nature. However, what they do to us, is they make us confused and we start seeking happiness in wrong ways, and the more we seek it in wrong ways the more confusion and suffering we generate. All this time the Buddha-nature stays perfect because all this confusion and suffering is included in it. Buddha-nature or natural suchness of things however they are, accommodates everything -- that's why it's unconditional and indestructible.

From this perspective, whether you are confused or enlightened does not make any difference -- anyway you are included in the Totality of the Vast Expanse. But subjectively, from sentient being's perspective, being confused or enlightened is a difference between suffering and cessation of suffering, so in that sense it makes a huge difference.

Makes sense? Confusion and enlightenment (or contamination vs. purification) exists only in one relative sense but in the ultimate sense all of those are a natural play of phenomena subsumed in the Buddha nature.

It seems like you're viewing buddha nature as essence. Freedom from imputations, conceptions, conventions, perspective, etc is buddha nature. But don't view it as essence, which would be a perpetuation of imputation of self and precisely what we are trying to avoid. Hope this helps.