And he's as endearingly autistic as ever:
The aggregate production function has proven to be a powerful and useful construct. Solow provides micro foundations based on the work of Houthaker. The aggregate or standin household utility function has proven to be a powerful and useful construct that rationalizes what use to be considered disparate micro and aggregate observations. Non-convexities are important as they give rise to the empirically observed high use of the extensive margin.