(9.128ab) If the general principle, the independent creator of all, has a threefold nature,
It is neither singular nor plural, and therefore does not exist.

We need to be very clear about what exactly it is we are refuting here and why. The Samkhyas are asserting an independent creator of all that is the nature of a general principle. They are not saying this general principle is Ishvara, an externally existent being that is the creator of all, they are saying this general principle is simply the external immutable laws of nature. In essence, they de-personify God, but still hold that there is an external process of creation that unfolds according to the laws of the general principle.

There are all sorts of theories in modern society that do exactly this, the most notable example being science as we understand it. The exact way that the Samkhyas assert how the general principle functions is not what is important here. Whether the general principle works this way, or that way, is not the point. None of us before reading Shantideva had ever heard of the Samkhyas or their explanation of the general principle, so of course we might think this refutation has nothing to do with us. This is why it is important for us to understand and identify the modern equivalents of the views of the other schools to see what they are talking about, and to identify how we still hold onto such views within our own mind.

If things exist inherently, they must be either singular or plural.  They cannot be both. This is because something that is inherently existent is one thing or another, and it does not exist independence upon anything else. That is the definition of inherent existence, not dependent upon anything else for its existence. If a singular thing has a plurality of parts, then that singular thing exist in dependence upon those parts, at which point it would no longer inherently be a singular thing.  If something is empty, in other words a mere creation of mind, then there is absolutely no problem for something to be simultaneously singular and plural, but neither singular or plural.  Again, to use the analogy of a hologram or the number six. Looked at from one angle a hologram appears as an elephant, looked at from another angle it may appear as a giraffe. So what is actually there, an elephant or a giraffe? Or looked at from one angle, a number looks like a six and looked at from another angle it looks like a nine. So what number is it, a six or a nine? The answer in both cases is it is simultaneously an elephant and a giraffe, but neither an elephant or a giraffe; and it is simultaneously a six and a nine, but neither a six or a nine.  In the same way, objects are neither singular nor plural, but both simultaneously depending upon how you look at them. In emptiness, this is no problem. Existing in multiple ways simultaneously without being one thing or another is the exact opposite of inherent existence. With inherent existence, we believe things are either singular or plural. They are one thing or another.

Quantum physics has gone a long ways towards unraveling this view as far as scientists are concerned, but most ordinary people do not understand quantum physics (myself included). The classic example of Schrodinger’s cat reveals how this works. In the thought experiment a cat is placed inside of a box in which there is a radioactive substance that has the power to kill the cat.  After some time has passed, the cat is either alive or dead. We exist in a state in which there are two possibilities – both are possible.  It is only when we open the box that reality organizes into one of these possibilities. Prior to opening the box, the cat exists in two states simultaneously, but is neither one or the other.  I am not a quantum physicist so I cannot say exactly how this is interpreted in science, but we can see a very clear correlation between this thought experiment and the hologram or the number six. All things exist in exactly the same way. Singularity and plurality is simply an example of how things can exist in multiple ways simultaneously. Our grasping at inherent existence says things cannot exist in multiple ways simultaneously, they exist in one way or another.