Can ideas prevent the economic stagnation predicted by the Solow model?

The Solow model suggests economies eventually hit a growth-free steady state. This video explains how ideas act as a critical variable that can shift the output curve, allowing for continuous growth by increasing productivity per unit of capital and labor.

The Solow model typically predicts that economies will eventually reach a steady state where growth stalls. However, by introducing ideas as a variable, the model accounts for 'cutting edge' growth. When ideas improve productivity, they generate more output from the same inputs of capital and labor. If the productivity variable, denoted as A, doubles from 1 to 2, the output curve shifts upward, causing investment to exceed depreciation and triggering further capital accumulation.

Continuous improvements in ideas keep the economy to the left of the steady state, sustaining growth. Ultimately, growth at the technological frontier depends on the rate at which new ideas are formed and the extent to which those ideas enhance productivity. This framework completes the Solow model by distinguishing between 'catching up' growth driven by capital accumulation and 'cutting edge' growth driven by innovation.

Source: The Solow Model and Ideas