In section 12.4, Keynes draws attention to how our conventional approach to long-term expectations, namely the assumption that the current state of affairs will continue, is certainly fallible, but that if it is held constant it may have beneficial effects. Specifically, he says that if the collective convention to believe in this stability persists, it afford the individual greater maneuverability to reassess investments and strategy. He also says that the ambiguity and precariousness of this convention contributes to our inability to reliably ascertain prospective yield and, by extension, the marginal efficiency of capital and its relation to interest rates.
unresolved Does this mean that this delusion of blithe stability can actually have self-reinforcing or self-fulfilling effects?