I repeat - they're all preparations.
From Nanavira's Shorter Note: Sankhara
From Nanavira's A Note on PaṭiccasamuppādaNanavira Thera wrote:the word sankhāra, in all contexts, means 'something that something else depends on', that is to say a determination (determinant).
Metta,Since to be sankhata and to be paticcasamuppanna are one and the same thing, we see that each item in the series of §17 is preceded by a sankhāra upon which it depends, and that therefore the total collection of items in the series depends upon the total collection of their respective sankhārā. In this sense we might say that the total collection of items is sankhārapaccayā. But since this statement means only that each and every particular item of the series depends upon a particular sankhāra, it does not say anything fresh. Sankhārapaccayā, however, can be understood in a different way: instead of 'dependent upon a collection of particular sankhārā', we can take it as meaning 'dependent upon the fact that there are such things as sankhārā'. In the first sense sankhārapaccayā is the equivalent of paticcasamuppanna ('dependently arisen'), and applies to a given series as a collection of particular items; in the second sense sankhārapaccayā is the equivalent of paticcasamuppāda ('dependent arising'), and applies to a given series as the exemplification of a structural principle. In the second sense it is true quite generally of all formulations of paticcasamuppāda, and not merely of this formulation (since any other formulation will consist of some other set of particular items). Paticcasamuppāda is, in fact, a structural principle (formally stated in the first Sutta passage at the head of this Note), and not one or another specific chain of sankhārā. It is thus an over-simplification to regard any one given formulation in particular terms as paticcasamuppāda. Every such formulation exemplifies the principle: none states it. Any paticcasamuppāda series, purely in virtue of its being an exemplification of paticcasamuppāda, depends upon the fact that there are such things as sankhārā; and a fortiori the series of §17 depends upon the fact of the existence of sankhārā: if there were no such things as sankhārā there would be no such thing as paticcasamuppāda at all, and therefore no such thing as this individual formulation of it.