After explaining the content coverage and elementary explanation of the basic dimensions of the paradigm of sustainable development, the concept of sustainability is considered in the light of preserving the total amount of capital in the production process, assuming no technological change and population growth. The research task set in this way brought to the fore the extremely complex question of the substitutability of produced and natural capital (stocks of natural resources and carrying capacity of the environment). The answer to it is directly related to the concept of weak and strong sustainability. The concept of poor sustainability allows substitutability between produced and natural capital, provided that the total amount of available capital does not decrease. On the contrary, the concept of strong sustainability implies a special observation of produced and natural capital. It practically eliminates the possibility of replacing one form of capital with another in the production process and from the point of view of the development economy is the only acceptable option in the long run. If unlimited substitution between natural and produced capital is allowed, then natural resources will eventually be depleted due to the creation of produced capital.