How is enlightenment or mindfulness reflected in the functioning of the aggregates?

This is a very interesting question and one I've been pondering as well! What follows is speculative and more based on reasoning than any specific teaching so please take with a big heap of salt... otoh I can't see how it obviously contradicts what is taught in my tradition?

First, I want to make a distinction between karma and the ordinary mechanics of the world. I don't think it can be said that karma drives the process of a maple seed turning into a maple tree. Why? Because karma is created by intention and action and maple trees are not sentient beings. And yet they age and are subject to causes and conditions. In a similar fashion, I think it is important to separate out the notion of karma from ordinary cause and effect or the mechanics of the world.

Now, one interesting thing to observe is that when a being is enlightened or achieves liberation in this very life the aggregates continue. It is not like upon achieving enlightenment that the body winks out of existence any more than the mind winks out of existence. Not only would that violate the conservation of energy ... it simply isn't the way we observe things to be. It would violate what is known to the world.

Indeed, even after an enlightened or liberated being dies in this very life their corpse remains. Not only does it remain, but with the break up of the body the atoms that were formerly a part of the body of an enlightened being continue. Conservation of energy and matter is observed.

The question could be reformulated maybe as what drives the aging of an enlightened beings body and mind after achieving enlightenment, but before death? For me, I find it inadequate to say that an enlightened beings aging and sickness are caused by past karma for various reasons. Rather, I think that karma must be extinguished upon the pacification of all afflictions. An enlightened or liberated being is no longer subject to suffering and thus past non-virtuous karma that is the cause of suffering must have been extinguished and laid down.

In exactly the same way that an enlightened or liberated beings corpse does not wink out of existence the moment they die I think neither does the mind.

Anyway, I post this not so much as an answer that others should rely upon because undoubtedly I'm very confused or made some egregious error. Rather, I'm hoping someone can help me learn something :)

This is quite self-explanatory from Itivuttaka 44 below on the relationship between enlightenment and the five aggregates:

This was said by the Blessed One, said by the Arahant, so I have heard: "Monks, there are these two forms of the Unbinding property. Which two? The Unbinding property with fuel remaining, & the Unbinding property with no fuel remaining.

And what is the Unbinding property with fuel remaining? There is the case where a monk is an arahant whose fermentations have ended, who has reached fulfillment, finished the task, laid down the burden, attained the true goal, ended the fetter of becoming, and is released through right gnosis. His five sense faculties still remain and, owing to their being intact, he is cognizant of the agreeable & the disagreeable, and is sensitive to pleasure & pain. His ending of passion, aversion, & delusion is termed the Unbinding property with fuel remaining.

And what is the Unbinding property with no fuel remaining? There is the case where a monk is an arahant whose fermentations have ended, who has reached fulfillment, finished the task, laid down the burden, attained the true goal, ended the fetter of becoming, and is released through right gnosis. For him, all that is sensed, being unrelished, will grow cold right here. This is termed the Unbinding property with no fuel remaining."

Commentary (Thanissaro):
With fuel remaining (sa-upadisesa) and with no fuel remaining (anupadisesa): The analogy here is to a fire. In the first case, the flames are out, but the embers are still glowing. In the second, the fire is so thoroughly out that the embers have grown cold. The "fuel" here is the five aggregates. While the arahant is still alive, he/she still experiences the five aggregates, but they do not burn with the fires of passion, aversion, or delusion. When the arahant passes away, there is no longer any experience of aggregates here or anywhere else.

How are the aggregates affected by a person's becoming enlightened or more enlightened?

As far as I understand , for an enlightened mind the aggregates will cease to exist because the mind will no longer cling to the aggregates. Because with the cessation of clinging, cessation of existence … cessation of birth … aging-and-death, sorrow, lamentation, pain, displeasure, and despair cease. The cessation of this whole mass of suffering will happen. This includes cessation of forms, feelings,perceptions, consciousness and volitional formations.

How does "mindfulness" affect the aggregates, what's the change (in the functioning of each aggregate) depending on whether or not you're being mindful?

To be mindfully aware of not clinging to the aggregates(as long as they are present) is mindfulness. Logically for a mindful person aggregates will cease to exist once enlightenment is achieved.

Is this a wrong question -- were/are the "aggregates" only taught in the context of their being something inconstant and not worth attaching to?

Aggregates are taught with reference to getting rid of the idea of self which is present in most of us. Conceiving self is like a disease and a person conceives self through the aggregates. Aggregates are taught in this context.

I have tried to answer logically based on whatever I have learned till now. Hope this helps.

In my understanding of their meaning, the "five heaps of wood" also known as The Five Aggregates, is a schema explaining phenomenological makeup of our subjective existence. In other words, everything that we can ever be aware of, is like a soup made from the following types of ingredients:

• Raw stimuli (rupa)
• Feelings (vedana)
• Notions (samjna)
• Memories (samskara)
• Interpreted Experiences (vijnana)

This may not be very precise from modern cognitive science perspective, but that's not the point. The point is to show how our entire world with its seemingly infinite complexity and troubles can be simplified to only a few ingredients. When one sees the world in terms of these ingredients, it seems almost comical to take the usual drama seriously. This is the true meaning of Satipatthana practice, to switch one's attention to a different descriptive framework, in order to enable emotional detachment and gain control over one's mind.

The way our subjective existence develops from scratch is explained in the teaching on Twelve Chainlinks, or nidanas:

1. Initial Non-differentiation (avijja)
2. Naive Imprinting or Accumulation of Memories (samskara)
3. Naive Interpretation (vijnana)
4. Naive Identification (namarupa) and Conceptualization (samjna)
5. Naive experience of ourselves as a "house with six doors" (salayatana)
6. Naive experience of "contact" with "external object" (phassa)
7. Naive association of internal feeling as something coming from the contact with an external object (vedana)
8. Craving for that experience (tanha)
9. Obsessing and pursuing of that experience (upadana)
10. Conflict with the world and resulting individuation (bhava)
11. Self-identification with the living organism (jati)
12. All kinds of trouble (jaramarana)

Again, I'm not sure I got all the details 100% right, but the main point is that subjective experience develops from complete non-differentiation -- to a full-blown individuation, through a series of steps that build on one another. Generally speaking, we learn to recognize and differentiate our experiences, until we develop attachments to some of them, and from this attachment comes a sense of conflict with the world which eventually arises as a notion of separate "I". Also note how four of these refer corresponding skandhas.

Because this process is entirely pre-conscious, we're only aware of its result - the experience of being a sentient being living in the world. We are not aware of the mechanisms at play, because we (=our experience of ourselves) are a result of this process! However, this process comes with a payload of trouble, due to the tendency of reification and conflict built into it's very foundation.

Enlightenment involves gradual liberation from the limitations of experience imposed by this process. This liberation is done through detachment from "realities" generated by the process (so called "self" and "world"), through increased awareness of the process' mechanisms and their implications, and through learning a new, higher, mode of perception that does not involve naive reification of our interpretations as the reality. As this Enlightenment progresses, we start seeing through the magic tricks of the process. In this sense we can say that the twelve steps of individuation are getting undone:

"Now from the remainderless fading & cessation of that very Ignorance comes the cessation of [Naive Imprinting]. From the cessation of [Naive Imprinting] comes the cessation of [Naive Interpretation]. From the cessation of [Naive Interpretation] comes the cessation of [Naive Identification and Conceptualization]. From the cessation of [Naive Identification and Conceptualization] comes the cessation of [Us-As-House-With-Six-Doors]. From the cessation of [Us-As-House-With-Six-Doors] comes the cessation of [Naive Experience of Contact]. From the cessation of [Naive Experience of Contact] comes the cessation of [Naive Attribution of Feeling]. From the cessation of [Naive Attribution of Feeling] comes the cessation of [Craving]. From the cessation of [Craving] comes the cessation of [Obsession/Pursuing]. From the cessation of [Obsession/Pursuing] comes the cessation of [Individuation]. From the cessation of [Individuation] comes the cessation of [Self-Identification-With-A-Living-Organism]. From the cessation of [Self-Identification-With-A-Living-Organism], then aging & death, sorrow, lamentation, pain, distress, & despair all cease. Such is the cessation of this entire [burning] heap of stress & suffering."

According to my teacher, the reason we learn Five Skandhas and the phenomenological mode, is to detach from the original "view" of the world, to stop assuming that our interpretation is reality. In order to facilitate this detachment we learn a different "view" (also known as "the raft") - the view of Five Skandhas etc. As we practice Satipatthana and get in the habit of maintaining this phenomenological view, we detach from the original naive view of the world and learn to control our mind. But this second view is not the ultimate reality either! It is only a provisional tool, designed to help us overcome our naive attachment to the first view. Once we develop enough insight, we realize that all views are just that, views, or interpretations - and none of them can be called primary. This liberation from all views, in practice, not just conceptually, leads to emergence of a new way of perception/cognition that in some sense can be called "multidimensional" or "transconceptual".

This transcendental perception is immune to reification, immune to attachment, and therefore immune to any sense of conflict and suffering.

Finally, to answer your question: with achievement of that transcendental perception, "the raft" is no longer necessary, so the Five Aggregates model is no longer relevant or applicable. We could certainly come back and say that Raw Stimuli remain more or less the same, that Feelings are no longer attributed to an external object, that Notions lose their solidity, that Memory Imprints are purified, and that Interpreted Experience is transcended - but this would be dragging ourselves back into confines of a view. So in this sense, Five Aggregates disappear, or are recognized as "empty":

Bodhisattva Avalokiteshvara, performing meditation in the deep Prajna-Paramita realized thus:
There are Five Heaps, and they by their nature are empty.
Hey Shariputra, rupa is emptiness, and emptiness if rupa. Emptiness is not different from rupa, and rupa is not different from emptiness. What is rupa is emptiness, what is emptiness is rupa. The same is true of Vedana, Samjna, Samsara, and Vijnana.

Shariputra, all phenomena have the character of emptiness.
They have no beginning and no end.
They are not pure, neither are they impure.
They do not decrease, neither do they increase.
Therefore, in emptiness, there is no Rupa, no Vedana, no Samjna, no Vijnana
...

This is why Buddha's subjective experience is called "indescribable" - because it actually transcends any single view.

Now, on intermediate stages of development, we may either catch a practitioner at a phase when he or she is squarely focused on seeing everything in terms of The Five Skandhas... or the next phase, when he or she is beginning to see the approximating/conventional nature of concepts... or the next phase, when he or she is beginning to lose solidity of any single view.

(I realize the above is far from being an obvious interpretation of Buddhism. However, this is what I've got from my decades of study and practice, under several different traditions, with live teachers, reading books, and meditating. So far, this is the only interpretative framework that fits with all sources and all traditions of Buddhism I have ever encountered. I don't claim omniscience, but I claim that I did my homework. You're free to ignore this, or you can try this on as a dress and see if it fits.)