here there is a great piece of the Grundisse which I found trying to make sense of what we were discussing earlier - how is the process of primitive accumulation related with the establishment of commodity production. Which one comes first?
Here, although the wording "original accumulation or primitive accumulation" would make us think otherwise, I think Marx is saying that the origin of the capitalist mode of production rests in the sphere of exchange. It is through the "“civilizing influence of external trade" (sigh!) that the process of transition to the capitalist mode of production start to realize itself. This, I think, for two main reasons.
First of all, through external commerce the product of labour is more and more – first only the surplus product, then the all of social production – is stamped with exchange value. The product is made into a commodity which value is determined by the quantity of socially necessary labour time embodied in it (dead labour).
Second, capital appears in its original form of merchant capital. It is the particular power-position of the mediator – ie the possibility of “outbargaining” and “cheating” (commercial profit not only appears as out-bargaining and cheating, but also largely originates from them - Volume III) – which allows the creation of capital before it becomes able to control the two poles of production which in the first phase is only able to mediate.
Here you have the first part of the fragment titled "Transition from Circulation to Capitalist Production" in the Grundisse (you can find it in Marxists.org). Quite usefully I think it goes back to the example used by Marx in the chapter on Primitive Accumulation - ie the expropriation of the commons in England. Here, though, Marx goes one step further back in his analysis and says that the reason behind the movement of primitive expropriation was the growing commerce with Holland and the creation of new needs and new possibilities of realizing surplus production.
So, I would say, the commodity comes first. After all - if capital is dead labor which valorizes itself sucking living labor - it means that the product of human labour has first of all to take the form of dead labor - ie it must take the form of exchange-value as opposed to simple use-value - and only then can, given the right social relations are established (through violence), rise up and sucks the living.
That's also why, i guess, the chapter on commodities and commodity fetishism comes first.
Is this making any sense? Please let me know because i am trying to think this through.