_a. Production is at the same time also consumption._ Twofold consumption, subjective and objective. The individual who develops his faculties in production, is also expending them, consuming them in the act of production, just as procreation is in its way a consumption of vital powers. In the second place, production is consumption of means of production which are used and used up and partly (as e. g. in burning) reduced to their natural elements. The same is true of the consumption of raw materials which do not remain in their natural form and state, being greatly absorbed in the process. The act of production is, therefore, in all its aspects an act of consumption as well. But this is admitted by economists. Production as directly identical with consumption, consumption as directly coincident with production, they call productive consumption. This identity of production and consumption finds its expression in Spinoza’s proposition, _Determinatio est negatio_. But this definition of productive consumption is resorted to just for the purpose of distinguishing between consumption as identical with production and consumption proper, which is defined as its destructive counterpart. Let us then consider consumption proper. Consumption is directly also production, just as in nature the consumption of the elements and of chemical matter constitutes production of plants. It is clear, that in nutrition, e. g., which is but one form of consumption, man produces his own body; but it is equally true of every kind of consumption, which goes to produce the human being in one way or another. [It is] consumptive production. But, say the economists, this production which is identical with consumption, is a second production resulting from the destruction of the product of the first. In the first, the producer transforms himself into things; in the second, things are transformed into human beings. Consequently, this consumptive production―although constituting a direct unity of production and consumption―differs essentially from production proper. The direct unity in which production coincides with consumption and consumption with production, does not interfere with their direct duality.