Symbol A_t

The passage around this formula

This is bookkeeping, not a finding. Its only content is what it forbids. Simon’s point was that $A_t$ is bounded by hours and by human processing capacity, and that this bound is not responsive to technology in the way that $G_t$ is. If $G_t$ rises by an order of magnitude, $\phi_t$ falls by an order of magnitude unless $c_v$ falls proportionally or $A_t$ expands proportionally. Institutions are the mechanism by which societies have historically pushed on $c_v$ . Nothing pushes usefully on $A_t$ .

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