The conception, for example, that the real value-element in all values is the socially required labor time objectified in them has been applied in both of these ways, and provides a standard, directly or indirectly applicable, which makes value fluctuate positively and negatively with respect to price. The fact of that single standard of value in no way establishes how labor power comes to be a value in the first place. It could hardly have done so if the labor power had not, by acting on various materials and fashioning various products, created the possibility of exchange, or if the use of the labor power were not perceived as a sacrifice which one makes for the sake of its fruits. Labor energy also, then, is aligned with the category of value only through the possibility and reality of exchange, irrespective of the fact that subsequently within this category of value labor may itself provide a standard for the remaining contents. If the labor power therefore is also the content of every value, it receives its form as value in the first place only because it enters into the relations between sacrifice and gain, or profit and value (here in the narrower sense).

DEFINE: Clarifies the distinction between the labor theory of value as a standard of measurement versus labor power's own entry into the category of value, which requires exchange. QUESTION: How exactly does sacrifice-and-gain framing (a subjective element) coexist with the objective labor-time standard within the same value category?

Georg Simmel, on individuality and social…, loc. 258