Simple average labour, it is true, varies in character in different countries and at different cultural epochs, but in a particular society it is given. More complex labour counts only as intensified, or rather multiplied simple labour, so that a smaller quantity of complex labour is considered equal to a larger quantity of simple labour. Experience shows that this reduction is constantly being made. A commodity may be the outcome of the most complicated labour, but through its value it is posited as equal to the product of simple labour, hence it represents only a specific quantity of simple labour.15 The various proportions in which different kinds of labour are reduced to simple labour as their unit of measurement are established by a social process that goes on behind the backs of the producers; these proportions therefore appear to the producers to have been handed down by tradition. In the interests of simplification, we shall henceforth view every form of labour-power directly as simple labour-power; by this we shall simply be saving ourselves the trouble of making the reduction. p. 135

Is intensified/multiplied labor referring to the use of fixed capital in production? I.e. the machinery as dead-labor whose value is then transferred to the product through living labor, intensifying the value transferred into a commodity per unit of labor-time? Or to forms of labor which are more difficult/intensive/complex?

If the latter, is Marx always considering that 1 hour = 1 hour? I understand how this works in the abstract, but I guess I am just curious how this has implications for the later imagined association of "free men" (though perhaps I am subjecting his "parallel" to too much scrutiny):

We shall assume, but only for the sake of a parallel with the production of commodities, that the share of each individual producer in the means of subsistence is determined by his labour-time. Labour-time would in that case play a double part. Its apportionment in accordance with a definite social plan maintains the correct proportion between the different functions of labour and the various needs of the associations. On the other hand, labour-time also serves as a measure of the part taken by each individual in the common labour, and of his share in the part of the total product destined for individual consumption. p 172

Both quotes from the Fowkes translation.

Reading section 3 now. I got confused about the relation between relative and equivalent forms on the one hand, and use value and exchange value on the other. Marx:

The value of A, thus expressed in the use value of B, has taken the form of relative value.

Also Marx:

The opposition or contrast existing internally in each commodity between use value and value, is, therefore, made evident externally by two commodities being placed in such relation to each other, that the commodity whose value it is sought to express, figures directly as a mere use value, while the commodity in which that value is to be expressed, figures directly as mere exchange value.

Am I reading this wrong or is he saying that in the equation x A = y B, B figures directly as mere exchange value, but at the same time the value of A is expressed in the use value of B? This is not clear to me unfortunately. Not the only idea I do not fully understand, but this feels like an important point.

Take a drink, every time he says "in so far as".... tbh, I'm honestly a bit confused by his sentence structure at times but I can understand...

I am 2/3 of the way in...