How does dependent origination and the skandhas fit together?

In my opinion, the Buddha used different models to explain different aspects of the subjective experience and the existential condition of unsatisfactoriness.

There are some points were some aspects of each model intersect, but you always have to remember that they are explaining different (but related) phenomena.

For example, the khandhas may be used to explain that nothing about what we use to consider as "I", "me", "myself" or "mine" is permanent and satisfactory, and so, nothing of that cannot be called "self". Basically, it uses our common knowledge about ourselves against "our"-"selves".

On the other hand, Dependent Origination is used to develop that idea of "not-self", and explains that instead of talking about selves that suffer, we should instead talk about impersonal processes that, conditioning one another, give rise to dukkha.

All the processes of DO are occurring because of the contact between khandhas and sense-stimuli. That's where they intersect. The cool thing about this superpositions is that each model does not contradict the other, but they complement each other.

Kind regards!

I will try to answer to the best of my abilities!

The Buddha found that all dhammas (phenomena, reality, things) depend on other dhammas to arise. That is how True reality works. Conditioned dhammas (conventional reality) arise beings as well. This is from the Khandhas, by clinging to them. By fully letting go of them, the Rebirth chain breaks.

Ignorance (Past Life)

Due to ignorance of the Dhamma, one cannot fulfill the Four Noble Truths.

Kammic Tendencies (Past Life)

With ignorance, Kammic imprints continue and certain accumulations of it cause certain Rebirths

Rebirth Consciousness (Past-Current Life)

“Carrying” Kamma, prior consciousness ceases, “propelling” into its new existence, “occupying” a shell.

Mind & Body (Current Life)

Through consciousness within a new shell, Khandhas arise, all depending on each other.

The Six Senses (Current Life)

With the establishment of the Khandhas, the six internal sense bases arise with sensual consciousness.

Contact (Current Life)

With the internal sense bases arising, it contacts its external counterparts due to its consciousness.

Sensations (Current Life)

This contact arises sensual feelings of either pleasantness, unpleasantness, or neutrality.

Desires (Current Life)

Pleasure-causing sensations begin to be naturally desired.

Clinging (Current Life)

These desires develop into clinging as one works to get the pleasure-causing sensations & avoid all else.

Becoming (Current-Future Life)

The Kamma formed within this life through clinging has not been extinguished, prompting Rebirth.

Birth (Future Life)

Because of becoming, a being cultivates decay that will not lead to the liberation, but another Rebirth.

Decay (Future-Past Life)

The Five Aggregates begin to slowly fail, and ignorance remains, fueling the continuity of Kamma.

Hope this helps!!!

Metta to all!

the exposition of dependent origination points out the root and conjoinment.

The doctrine of 'aggregates' is a system of language based on what can be known about the referable reality.

It is inferred from the beginning, of agreeing on that there is that which can be thought about, that which is thought about is whatever it is and what we think it is is merely thinking.

So in other words if agree that there is "something" and that we can call "referable reality" or "existence" or "being". Whatever we call it, that is only a name for it. Whatever we know about it is merely knowledge and knowledge is not that which is the object of knowing.

So this "something" we can say it is "All" and point out that reality as it is experienced is in 6 ranges; imagination, seeing, smelling, hearing, tasting, bodily sensibity. So we can say that these are to be discerned and agreement can be reached on this.

Furthermore one can know that the word "Seeing" is not that which is called "Seeing" because "Seeing" does not exist when "Eye" doesn't exist.. when "Forms cognizable by the Eye" don't exist, when there is no "Consciousness".

Now we introduced 4 new elements to this language system but all of these words have a demonstrable basis.

The complete inference of the doctrine of Aggregates would in brief continue like this; - Infer Contact to be discerned as a separate condition coming into play - Infer that Allness of the All is absolute and if All is conditioned it is not conditioned by something outside of it's range; Allness is absolute, if All is directed it would be self-directed; That which directs and supports the All is included in the All.

If this can be agreed upon then one has inferred Intention which is Formations Aggregate. From Intention one can infer Knowledge & Discernment as requisite condition. From Discernment faculty one can infer Ignorance due to lack of development. Here one infers "power of discernment" and so on.

What is left is only the pointing out of the root condition by means of dependent origination and similes to illustrate the conjoinment.

Dependent origination is about the origination of suffering (sorrow, grief, despair, etc) that comes from ignorantly attaching to the khandhas as 'self' ('upadana') and as 'a being' ('jati'). Not only is attachment itself a mental state fraught with anxiety & stress, but the sorrowful traumatic idea of 'aging-&-death' occurs when the khandhas attached to as 'self' or 'a being' are inevitably subjected to impermanence. SN 12.66 says:

‘The many diverse kinds of suffering that arise in the world headed by aging-and-death: this suffering has acquisition as its source, acquisition as its origin; it is born and produced from acquisition. When there is acquisition, aging-and-death comes to be; when there is no acquisition, aging-and-death does not come to be.’

The word "acquisition' ('upadhi') above is a synonym for 'attachment' ('upadana'). SN 12.66 is one of many suttas that shows the word 'jati' in Dependent Origination does not mean 'physical birth'. Instead, 'jati' ('birth') means 'identifying' with something as 'self', 'mine' or 'a being'. MN 26 says:

And what may be said to be subject to birth? Spouses & children are subject to birth. Men & women slaves... goats & sheep... fowl & pigs... elephants, cattle, horses, & mares... gold & silver are subject to birth. Subject to birth are these acquisitions, and one who is tied to them, infatuated with them, who has totally fallen for them, being subject to birth, seeks what is likewise subject to birth.

For a more simple explanation of how attachment to the khandhas results in suffering when the khandhas change due to impermanence, SN 22.1 says:

"Now, how is one afflicted in body & afflicted in mind?

"There is the case where an uninstructed, run-of-the-mill person — who has no regard for noble ones, is not well-versed or disciplined in their Dhamma; who has no regard for men of integrity, is not well-versed or disciplined in their Dhamma — assumes form (the body) to be the self, or the self as possessing form, or form as in the self, or the self as in form. He is seized with the idea that 'I am form' or 'Form is mine.' As he is seized with these ideas, his form changes & alters, and he falls into sorrow, lamentation, pain, distress, & despair over its change & alteration.

"He assumes feeling to be the self, or the self as possessing feeling, or feeling as in the self, or the self as in feeling. He is seized with the idea that 'I am feeling' or 'Feeling is mine.' As he is seized with these ideas, his feeling changes & alters, and he falls into sorrow, lamentation, pain, distress, & despair over its change & alteration.

"He assumes perception to be the self, or the self as possessing perception, or perception as in the self, or the self as in perception. He is seized with the idea that 'I am perception' or 'Perception is mine.' As he is seized with these ideas, his perception changes & alters, and he falls into sorrow, lamentation, pain, distress, & despair over its change & alteration.

"He assumes (mental) fabrications to be the self, or the self as possessing fabrications, or fabrications as in the self, or the self as in fabrications. He is seized with the idea that 'I am fabrications' or 'Fabrications are mine.' As he is seized with these ideas, his fabrications change & alter, and he falls into sorrow, lamentation, pain, distress, & despair over their change & alteration.

"He assumes consciousness to be the self, or the self as possessing consciousness, or consciousness as in the self, or the self as in consciousness. He is seized with the idea that 'I am consciousness' or 'Consciousness is mine.' As he is seized with these ideas, his consciousness changes & alters, and he falls into sorrow, lamentation, pain, distress, & despair over its change & alteration.

"This, householder, is how one is afflicted in body and afflicted in mind.

We should study the whole of SN 22.1 thoroughly until we understand it clearly. SN 22.1 is spoken in simple language and is not rocket science.

All of the above is reflected in the most brief explanation of Dependent Origination, from MN 28, below:

Now this has been said by the Blessed One: “One who sees dependent origination sees the Dhamma; one who sees the Dhamma sees dependent origination.” And these five aggregates affected by clinging are dependently arisen. The desire, indulgence, inclination, and holding based on these five aggregates affected by clinging is the origin of suffering. The removal of desire and lust, the abandonment of desire and lust for these five aggregates affected by clinging is the cessation of suffering.’

As for the khandhas, they are merely the components of life. To help give up attachment to the khandhas, SN 22.59 explains the khandhas are unsatisfactory (cannot bring true happiness) & not-self because each khandha, when examined closely, is impermanent and selfless.