"Animal Spirits" was a secondary variable supporting Keynes's interval valued probability and evidential weight of the argument analysis

Proponents  of the animal spirits hypothesis,who argue that animal spirits are the primary point that Keynes was making in the General Theory, such as Marchionatti (1999),  Akerlof  and Shiller (2009),Dow and Dow (2012), and Shiller (2021),  fail to grasp Keynes’s lifelong emphasis on (a) imprecise probability, as opposed to the precise probability concept underlying  Benthamite Utilitarian and neoclassical economics and (b)to confuse and conflate confidence with animal spirits in Keynes’s discussions on pp.161-163 of the General Theory in chapter 12,which is a non-technical rewrite of Keynes’s chapter XXVI, which was based on chapter VI ‘s evidential weight of the argument, in  Keynes’s A Treatise on Probability. Keynes ‘s point was that the liquidity preference option, which Keynes believed was the logical option to choose if faced with ignorance or extreme uncertainty at the micro level, leads to the collapse of the macro economy as spending flows stop.

Keynes’s Chapter 12 of the General Theory was written especially for economists. Keynes does not discuss animal spirits in the A Treatise on Probability. However, George Boole, upon whom Keynes based his A Treatise on Probability, did discuss the impact of the decision makers feelings and emotions on the mental state of the decision maker. G. Boole (1854, pp.244-245; p.272) was the first to point out that the process of  expectation formation is not merely a purely  mathematical, probabilistic calculation ,but is affected by emotional considerations  which impact  the mental state of the decision maker. The feelings of the decision maker are thus  aspects that impacted in the process of  the calculation of the expectation. Since  Keynes did not cover this in his A Treatise on Probability, Keynes took the opportunity in chapter 12 of the General Theory to incorporate Boole’s point into his discussions on pp.161-163,differentiating ,just like Boole did before him  ,between exact ,precise probability, made under the assumption of a complete, information set ,so that a complete ordering of all probabilities is possible in the probability space ,which are point estimates ,and inexact ,imprecise probability, which are interval estimates, which are made under conditions of partial information, so that  only a partial ordering of the probability space is possible .