According to the Prasangika school, the object of refutation (or negation, gag-cha) is an extremely subtle object that is ever so slightly more than—a little over and above—what is merely labeled by the mind. The object of refutation is what appears to us; it is that in which we believe.

In order to attain liberation from the entire round of suffering and its cause, we need to cut its very root, the fundamental ignorance that keeps us in it. Of the many kinds of ignorance, which is the specific one that we have to eradicate? It is not the concept that believes the bell to exist the way it appears, which is what the texts usually describe as the root of samsara—except that in the case of the root of samsara, we should be talking about the I, not the bell that I’ve been using as an example here.

When the I appears to us, we believe that there is something slightly over and above what is merely labeled by the mind and that this is how the I exists. Then we believe that this is one hundred percent true and let our mind hold on to that. It is this specific, particular ignorance that is the root of all delusion, karma and suffering. This very one. It’s not just any type of ignorance—it’s this one.

As well as this kind of ignorance, there’s the one described by the second Madhyamika school, the Svatantrika—the hallucination on the I, the object to be refuted according to their view. I’m just mentioning this so that you’ll have an idea of how trapped our minds are, how many different levels of ignorance we experience, how many kinds of hallucination there are.

The hallucination on the I that the Svatantrikas describe is grosser than the one the Prasangikas explain. Then there’s the Cittamatrins’ version, where they say that the I exists from its own side without depending on mental imprints, without the mind as creator. They describe a seventh level of consciousness—normally we talk about just six—that is called the basis of samsara and nirvana. So they say that the I exists totally from its own side without depending on imprints left on this seventh level of consciousness and describe it as a self-entity.

According to Hindu philosophy, the I, which they call atman, is permanent. While the self is actually impermanent, they believe it to be permanent. Therefore, there’s a lot of discussion in Buddhist texts refuting this view, explaining that while the self may appear to us to be permanent, in fact it changes moment by moment due to causes and conditions and is therefore impermanent. If you look at your I right now, you’ll see that it appears to be permanent, whereas you know that in reality it is impermanent in nature.

Other views hold, for example, that while the I is dependent upon parts, there is the appearance and the belief that it exists alone, not dependent upon parts, or that while the I is dependent upon causes and conditions, there is the appearance and the belief that it exists with its own freedom, without depending on causes and conditions.

These gross hallucinations are described and posited as the object of refutation by the first Buddhist school, the Vaibashika. This school has eighteen divisions, each with its own variant view. Then there’s the hallucination that even though the I exists dependent upon the group and continuity of the aggregates, it appears to us as a self-entity existing without depending on the group and continuity of the aggregates. So these are some of the positions held by the Vaibashika and the Sautrantika, the lower Buddhist schools.

How has it come about that there are these four schools of Buddhist philosophy?

It’s due to the different ways of explaining what the I is. In reality, emptiness is just one, not many. There is only one emptiness that directly cuts the root of samsara. This is the emptiness taught by the Prasangika-Madhyamika school, whose view of emptiness is the unmistaken, pure one and the only one that can cut the specific ignorance that I mentioned before.

However, not everybody has the karma to accept this, to understand this, to realize this. Sentient beings have different levels of mind. Therefore, the all-knowing, kind, compassionate Buddha taught varying levels of philosophy to guide sentient beings’ minds gradually up to the level where they could realize the Prasangika view of emptiness.