Is it the skandhas that cause us suffering, or the attachment to them?
Thanks [EDIT: Topic title edited to provide greater clarity of the question at hand - Retro.]
It is merely an arbitrary manner of description and doesn't really matter either way. That is, saying suffering is strictly skandhas or strictly attachment would be one-sided either way.
First of all, if you consider the Twelve Nidanas, suffering results from the cyclical process of the chains of dependent-origination. Within that cycle, it is arbitrary to pick a "center point," in fact, this seems to be exactly what it means to be attached to a self. If it is so arbitrary, then one sees that suffering is conditioned by skandhas, but these skandhas are themselves condition and are conditioned by by non-skandhas such as attachment. So, should attachment itself be called an "aggregate"? If it's a fixed aspect of dependent origination, this would seem to suggest so. If we deny that it's an aggregate, because it's not one of the Five Aggregates
, yet it's still one of the Twelve Nidanas, then the term "aggregate" doesn't really carry a lot of meaning. Aren't the Nidanas which aren't skandhas also constituents of our experience too? Of course, but the non-skandha items of the Twelve Nidanas are distinguished from the existentially neutral, mental-physical processes of the Five Skandhas, whereas craving and attachment is something we add
to them and suffering is something that results from this.
Secondly, to answer this question, it might be good to consider a different question. Because suffering is said to be conditioned by craving, and craving is said to be conditioned by ignorance, it might be good to then ask, "Is ignorance itself a skandha?" I've already pointed out how, in a manner of speaking, craving & attachment can be regarded as skandhas. The same seems to apply to ignorance and suffering, though this doesn't change their nature. Instead, it's only an arbitrarily different manner of description.
The Buddha, after his Great Awakening, nonetheless remained a collection of khandhas. Devoid of "craving through ignorance", that is.
The Buddha extinguished his delusion of self. Many Buddhists, both Theravada and Mahayana, try to carry a burning torch the Buddha didn't light, by arguing over whether he was an impermanent lump of skandhas that decayed or an eternal, transcendental spirit which only has the illusion of birth & decay. Both views seems to miss the point of anatta.
Also, this answer seems to be very good and succinct:
Visākha: “Lady, is that grasping the same as these five aggregates affected by grasping, or is the grasping something apart from the five aggregates affected by grasping?”
Bhikkhuṇī Dhammadinnā: “Friend Visākha, that grasping is neither the same as these five aggregates affected by grasping nor is grasping something apart from the five aggregates affected by grasping. It is the desire and lust in regard to the five aggregates affected by grasping that is the grasping there.”