Hi @Gabriel_L and Ven. @anon61506839,
I shall be most happy to provide my perspective on this. Whether it will clarify things is, of course, an entirely different matter!
In a nutshell I think you are both right. I agree with Gabriel that the main meaning of saṅkhāra in the EBTs is “intentional activity”, and as such it is synonymous with kamma. On the other hand, I agree with Ven. Dhammarakkhita that saṅkhāra is used broadly, and that its various meanings must be carefully distinguished according to context.
When looking at this sort of question I usually ask myself what are the main context in which a particular word occurs. If this question can be answered with a degree of certainty, then we should be able to establish the default meaning of the term, with other meanings being of subsidiary importance. The two main doctrinal contexts for saṅkhāra in the EBTs are the five khandhas and dependent origination. What it means in the context of the five khandhas (“personality factors”) can be seen from the following two EBT quotes:
Katame ca, bhikkhave, saṅkhārā? Chayime, bhikkhave, cetanākāyā – rūpasañcetanā, saddasañcetanā, gandhasañcetanā, rasasañcetanā, phoṭṭhabbasañcetanā, dhammasañcetanā. Ime vuccanti bhikkhave, saṅkhārā.
And what, bhikkhus, are volitional formations? There are these six classes of volition: volition regarding forms, volition regarding sounds, volition regarding odours, volition regarding tastes, volition regarding tactile objects, volition regarding mental phenomena. This is called volitional formations. (SN 22.56/57)
Kiñca, bhikkhave, saṅkhāre vadetha? Saṅkhatamabhisaṅkharontīti kho, bhikkhave, tasmā ‘saṅkhārā’ti vuccati. Kiñca saṅkhatamabhisaṅkharonti? Rūpaṃ rūpattāya saṅkhatamabhisaṅkharonti, vedanaṃ vedanattāya saṅkhatamabhisaṅkharonti, saññaṃ saññattāya saṅkhatamabhisaṅkharonti, saṅkhāre saṅkhārattāya saṅkhatamabhisaṅkharonti, viññāṇaṃ viññāṇattāya saṅkhatamabhisaṅkharonti. Saṅkhatamabhisaṅkharontīti kho, bhikkhave, tasmā ‘saṅkhārā’ti vuccati.
And why, bhikkhus, do you call them volitional formations? ‘They construct the conditioned,’ bhikkhus, therefore they are called volitional formations. And what is the conditioned that they construct? They construct conditioned form as form; they construct conditioned feeling as feeling; they construct conditioned perception as perception; they construct conditioned volitional formations as volitional formations; they construct conditioned consciousness as consciousness. ‘They construct the conditioned,’ bhikkhus, therefore they are called volitional formations. (SN 22.79)
In the first two suttas (SN 22.56 + 57) saṅkhāra is explicitly equated with cetanā/sañcetanā, cetanā being the term which is normally used to define kamma. So here saṅkhāra is used interchangeably with kamma. In the second sutta the saṅkhāras are said to be that which produces existence and hence again they are indistinguishable from kamma. This, I think, is an important finding, because it sets a fairly unambiguous benchmark for our interpretation of saṅkhāra.
Let’s turn to dependent origination. Here are a couple of instructive quotes:
Yattha atthi saṅkhārānaṃ vuddhi, atthi tattha āyatiṃ punabbhavābhinibbatti.
Where there is the growth of volitional formations, there is the production of future renewed existence. (SN 12.64)
Sāmaṃ vā taṃ, ānanda, kāyasaṅkhāraṃ/vacīsaṅkhāraṃ/manosaṅkhāraṃ abhisaṅkharoti, yaṃpaccayāssa taṃ uppajjati ajjhattaṃ sukhadukkhaṃ. Pare vā taṃ, ānanda, kāyasaṅkhāraṃ/vacīsaṅkhāraṃ/manosaṅkhāraṃ abhisaṅkharonti, yaṃpaccayāssa taṃ uppajjati ajjhattaṃ sukhadukkhaṃ. Sampajāno vā taṃ, ānanda, kāyasaṅkhāraṃ/vacīsaṅkhāraṃ/manosaṅkhāraṃ abhisaṅkharoti yaṃpaccayāssa taṃ uppajjati ajjhattaṃ sukhadukkhaṃ. Asampajāno vā taṃ, ānanda, kāyasaṅkhāraṃ/vacīsaṅkhāraṃ/manosaṅkhāraṃ abhisaṅkharoti yaṃpaccayāssa taṃ uppajjati ajjhattaṃ sukhadukkhaṃ.
Either on one’s own initiative, Ᾱnanda, one generates that bodily/verbal/mental volitional formation conditioned by which pleasure and pain arise internally; or prompted by others one generates that bodily/verbal/mental volitional formation conditioned by which pleasure and pain arise internally. Either deliberately, Ānanda, one generates that bodily/verbal/mental volitional formation conditioned by which pleasure and pain arise internally; or undeliberately one generates that bodily/verbal/mental volitional formation conditioned by which pleasure and pain arise internally. (SN 12.25)
Both of the above suttas are found in the Nidāna-samyutta and so the context is dependent origination. Saṅkhāra is here connected to rebirth and the future arising of pleasure and pain. Once again it seems fairly clear that this refers to kamma. Given our previous finding of what saṅkhāra means in the context of the five khandhas, the case for this is strong. (Ven. Bhikkhu Bodhi discusses the meaning of saṅkhāra in the context dependent origination at length here.)
Since the two main doctrinal contexts for saṅkhāra concern kamma, we should assume that this is the general meaning of the word, unless the context demands otherwise. Let’s look at a couple of such contexts.
In the well-known phrase sabbe saṅkhāra dukkhā it is almost unavoidable to conclude that saṅkhāra must be broader than volition or kamma. Since it is the five khandhas that are dukkhā, in the present context saṅkhāra must refer to all conditioned phenomena. In other words, saṅkhāras are created by saṅkhāras as a constructive force. That saṅkhāra refers to both the active side of creating as well the passive side of that which is thus created is a peculiarity of this word. There is a clear link between the two, but it is difficult to render both sides with a single word in English, which is what leads most translators to choose several words to render saṅkhāra, with each word being relevant to a specific context.
There are also context where saṅkhāra is used to mean “effort”, not just the intention that originates the effort. In these contexts the meaning is close to kamma, but somewhat expanded.
So saṅkhāra is a relatively complex word. However, once you get the idea that it refers both to that which creates and to that which is created it is fairly straightforward. But of these two meanings the creative aspect is much more important in the suttas. That’s how is seems to me.