Imagine a source of light, such as a sun, appearing in an endless dead void.

As the light spreads through the void, any region it reaches is first enlightened just a tiny bit. Gradually, more light seeps in. The region grows increasingly luminous, until eventually, there's no difference between it and the center of the light source. It has, in fact, become part a new part of the original light source. The process continues in the same way, in regions beyond the one we just examined. The process as a whole can be described simply as the original light source growing.

Now consider the light source as Nibbana, the ultimate, infinite freedom. As it grows, it first creates regions with a tiny degree of freedom: inanimate matter. Which only has the freedom to take up space.

As more light seeps in, forms with greater degree of freedom are created: living forms.

Initially these are merely plants, which have very limited freedom, for example to grow and shape themselves.

Eventually animals will emerge. Animals have more freedom than plants, and as they evolve from simple single-cell organism, to more sophisticated complex organisms composed of numerous cells and organs, their degree of freedom grows.

They acquire growing levels of consciousness, and increasingly approach contemplative consciousness, which we have as humans and is a quantum leap in freedom, though in some ways a double-edged sword.

At some basic level, every thing which exists is endowed with a tendency to exist. In inanimate matter, this is manifest in how the matter will remain the same - not change or move at all - unless acted upon by some external force. Plants clearly struggle to survive, just consider the sapling or even blade of grass twisting itself towards the light necessary for its survival.

For every living thing, the desire to exist is clearly a fundamental quality. As the life form evolves, this desire is buttressed by instincts that grow ever more sophisticated, until it matures into consciousness, in a sense - the ultimate survival instinct. The animal is now able to reason about its own survival.

The drive to survive becomes increasingly more conscious and deliberate, until it ripens fully into contemplative consciousness, which allowed us humans to build weapons and forts and granaries and take over the planet. But also direct it freely towards any object, including - reflectively - its own self, its own nature and the very nature of existence.

This level of consciousness is the ultimate goal of the process because such consciousness can contemplate and ultimate realize its own true nature. This teaching is not exclusive to Buddhism or even Eastern philosophy as a whole: The maxim "know thyself" was carved into the gate of the Temple of Apollo - God of reason - in Delphi, and later made a cornerstone of Western philosophy by Socrates and Plato.

Indeed, this knowledge isn't so much learning of the new, but a return. With enlightenment, consciousness is able to come back to its source, the great light whence its own light came: Nibbana. For example, Socrates taught there is no such thing as "learning something new", only remembering that which is already there but obscured by forgetfulness.

What I like about this theory is that it elegantly answers a question that bothered me for a while: the nature of the defilements.

According to this theory, the defilements are not some external pollution, but just a primitive state of enlightenment. The defiled state is merely a state of transition between absent and absolute freedom. It's a spectrum.

Contemplative consciousness, and its functional product - free will - allow us to reverberate any sensation by reflecting upon it.

As stated before, this is a double edged sword.

We can choose to reflect, and thus multiply, upon our survival instincts. This multiplies them ad-infinitum, such that simple instincts are multiplied into greed, and greed becomes infinite - an infinite hunger, first for sensual stimulation, but later, when the capacity of our senses to take in more stimulation is exhausted, we abstract our desires into purely symbolic forms: hunger for infinite amounts of power, money, "fame", etc.

This is how karma is created.

This self-reflecting, self-reverberating process can amplify every sensation. That is why humans can suffer so much more than animals, let alone plants or inanimate objects.

An animal will always be struck with the one arrow. A human, contemplating this strike, will reverberate it, striking his own self with the second, third, fourth, any number of arrows.

The most evolved humans, with the greatest level of consciousness, are thus those with the greatest capacity to inflict suffering upon themselves.

This whole process of conscious, deliberate contemplation is the root of karma, and I expect that animals cannot create karma, or only minimally, due to their nearly absent level of consciousness.

This is the capacity of the beings with contemplative consciousness to ill-use it to amplify their own attachments. The principal attachment to existence, which Buddhism calls taṇhā, its two subsidiaries: desire for states that appear to aid and enhance survival (lobha), aversion for states that seem to hinder and diminish survival (dosa). These are both accompanied by the necessary factor that will makes attachment to existence itself seem crucial: the obscuration of the light source whence consciousness originated, or in Buddhist terms its own true nature.

So far about the capacity of contemplative consciousness to amplify its base instincts and create karma. But it can also be directed towards itself, and if done correctly, realize its own true nature.

In this process, it will realize that the self is nothing more than a powerful, involved, and sophisticated complex of survival instincts.

The ultimate achievement possible for consciousness, with correct direction at contemplating its own self, raising doubt at its instinctual representation of the world (name and form, nama rupa) as a symbolic battleground of desire and aversion, where the goal is survival, existence. Exposing delusions such as the possibility of physical forms persisting forever, without change or death - the ultimate survival fantasy, the delusion to satisfy all our primitive instinctual drives to survive. Or another delusion, that if only we attain our next goal - that next promotion, sexual conquest, house, car, figure in our bank account - we will abide in eternal bliss in this very life. Of course, our instincts will never relent in their battle to survive, our happiness is not their goal, and reaching any milestone will only allow them to pull us tirelessly towards the next, until our body is exhausted and breaks apart.

By realizing our true nature, our inseparable union with the great light source - Nibbana - we can abandon the primitive halfway state of existence. As we progress towards this realization, it is as if our bodies become more illuminated. Eventually, there is only the light, and physical existence is abandoned.

This can also be conceptualized as a gradual process of refining one substance to another. For example, refining crude oil into gasoline. Initially there is just crude oil (or more accurately, there is nothing). Then there's 1%, 2%, 3% gasoline (or more luminous). Eventually, there is only gasoline (or pure light without darkness, or the opposite of nothing: everything).

The defiled state is just a half-state somewhere between these two extremes.

I very much welcome comments. To give some context, this theory was born out of intense contemplation of a question that always bothered me: why are there defilements?

It's the best explanation I found so far, and I rather like it, but I try not to get attached ;-)