Socially Necessary Labour Time Quotes

“Every commodity has value in so far as it incorporates
socially necessary labour time, and is the outcome of a social process
of production. It enters the process of exchange as a bearer of value.
This is the sense of Marx's remark that, `the act of exchange gives to
the commodity converted into money, not its value, but its specific
value form'. /Capital, /vol. I, p. 103. [MECW 35, p101]”
― Rudolph Hiferding, Finance Capital: A study in the latest phase of capitalist development

“Exchange is thus accessible to analysis because it not only satisfies
individual needs, but is also a social necessity which makes individual
need its instrument while at the same time limiting its satisfaction.
For a need can be satisfied only to the extent that social necessity
will permit. It is of course a presupposition, for human society is
inconceivable without the satisfaction of individual needs. This does
not mean, however, that exchange is simply a function of individual
need, as indeed it would be in a collectivist economy, but that
individual needs are satisfied only to the extent that exchange allows
them to participate in the product of society. It is this participation
which determines exchange. The latter appears to be simply a
quantitative ratio between two things,[4] <#n4> which is determined when
this quantity is determined. The quantity which is turned over in
exchange, however, counts only as a part of social production, which
itself is quantitatively determined by the labour time that society
assigns to it. Society is here conceived as an entity which employs its
collective labour power to produce the total output, while the
individual and his labour power count only as organs of that society. In
that role, the individual shares in the product to the extent that his
own labour power participates, on average, in the total labour power
(assuming the intensity and productivity of labour to be fixed). If he
works too slowly or if his work produces something useless (an otherwise
useful article would be considered useless if it constituted an excess
of goods in circulation), his labour power is scaled down to average
labour time, i.e. socially necessary labour time. The aggregate labour
time for the total product, once given, must therefore find expression
in exchange. In its simplest form, this happens when the quantitative
ratios between goods exchanged correspond to the quantitative ratios of
the socially necessary labour time expended in their production.
Commodities would in that case exchange at their values.”
― Rudolph Hiferding, Finance Capital: A study in the latest phase of capitalist development

“Commodities are the embodiment of socially necessary labour time. But
labour time as such is not expressed directly, as it is in the society
envisaged by Rodbertus, in which the central authority establishes the
unit of labour time which it will accept as valid for each commodity.
Labour time is expressed only in the exchange commensurability of two
articles. Thus the value of an article, i.e., its average time of
production, is not expressed directly as eight, ten or twelve hours, but
as a specific quantity of another article. In other words, a natural
object with all its material attributes expresses the equivalent value
of another thing. For example, in the equation, one coat equals twenty
metres of linen, the twenty metres of linen are the equivalent of one
coat simply because both are embodiments of socially necessary labour
time. It is in this sense that all commodities are commensurable.”
― Rudolph Hiferding, Finance Capital: A study in the latest phase of capitalist development