Animal spirits: Keynes' theory of rational investment decision-making under conditions of fundamental uncertainty

Keynes's term, animal spirits, has been mistakenly confused with irrational decision-making. However, if we accept Keynes' assumption that future is fundamentally uncertain and nonergodic, animal spirits become key factor that makes continual process of investment decision-making possible. On the other hand, if animal spirits blunt, investment activity dwindles and makes emergence of deep economic crisis likely.