That is, only that which is the product of abstract labor has value in capitalism. Capital is a social relation of abstract labor. As the repository of surplus value, capital is driven to constantly go beyond itself, irrespective of natural or human-imposed limits. Herein lies the secret of capital's enormous productivity as well as its destructiveness. Capital is the endless and limitless drive to go beyond its limiting barrier.
Every boundary is and has to be a barrier for it.
For this reason any effort to control capital without uprooting the basis of value production is ultimately self-defeating. This is the tragic lesson of the past century. Many socialists thought it was possible to control capital through the welfare state or government intervention. Such Social-Democratic experiments all ended in total failure. That too proved to be a total failure, as seen in the exploitative nature of the state-capitalist societies which arose in Russia, China, Cuba and elsewhere.