In a Potemkin Review interview conducted by Antoine Dolcerocca and Gokhan Terzioglu, Thomas Piketty discusses what he believes is the source of long-term, even permanent, productivity, which, of course, can occur without reasonably equitable distribution, the main focus of his book Capital in the 21st Century. An excerpt:

Question:

What do you see as a source of perpetual productivity growth?

Thomas Piketty:

Simply accumulation of new knowledge. People go to school more, knowledge in science increases and that is the primary reason for productivity growth. We know more right now in semiconductors and biology than we did twenty years ago, and that will continue.

Question:

You argue in the book that while Marx made his predictions in the 19th century, we now know that sustained productivity growth is possible with knowledge (Solow residual, etc.). But do you think this can be a sustained process in the long run?

Thomas Piketty:

Yes, I do think that we can make inventions forever. The only thing that can make it non-sustainable is if we destroy the planet in the meantime, but I do not think that is what Marx had in mind. It can be a serious issue because we need to find new ways of producing energy in order to make it sustainable, or else this will come to a halt. However if we are able to use all forms of renewable energy, immaterial growth of knowledge can continue forever, or at least for a couple of centuries. There is no reason why technological progress should stop and population growth could also continue for a little more.•