From the humanity theory of Das Kapital, people should and must develop low-carbon economy, but carbon from economic activity is not the lower the better, not even eliminating carbon and an economy without carbon may not be the humanity economy. From the liberty theory of Das Kapital, the amount of carbon from economic activity reffects the process of freedom realization. To develop the low carbon economy in modern society, science and technology is the key, and the principle of doing things in the limit of one's ability is the basic rule. Fro...