▁world ▁would ▁be ▁today !” ▁Many ▁of ▁Ke yn es ' ▁ideas ▁that ▁became ▁the ▁basis ▁of ▁Ke yn esian ▁econom ics ▁are ▁influenced ▁by ▁Princi ples ▁of ▁Political ▁Econom y . ▁Although ▁Mal th us ▁fails ▁to ▁connect ▁long - run ▁supply ▁and ▁demand ▁curve ▁as ▁setting ▁the ▁natural ▁price ▁of ▁an ▁item , ▁Mal th us ▁is ▁one ▁of ▁the ▁first ▁to ▁describe ▁the ▁natural ▁price ▁of ▁an ▁item . ▁Ke yn es ▁util izes ▁this ▁idea ▁and ▁also ▁draw s ▁on ▁Mal th us ' ▁concept ▁of ▁government ▁sp ending ▁during ▁times ▁of ▁economic ▁crisis . ▁Ke yn es ▁c ites ▁this ▁chapter ▁of ▁Mal th us ' ▁book ▁as ▁" a ▁master ly ▁ex position ▁of ▁the ▁conditions ▁which ▁determine ▁the ▁optim um ▁of ▁saving ▁in ▁the ▁actual ▁economic ▁system ▁in ▁which ▁we ▁live ." ▁ ▁However , ▁Ke yn es ▁also ▁crit iques ▁Thomas ▁Mal th us . ▁He ▁fault s ▁Mal th us ' ▁work ▁for ▁being ▁" un able ▁to ▁explain ▁clearly ▁( ap art ▁from ▁an ▁appeal ▁to ▁the ▁facts ▁of ▁common ▁observation ) ▁how ▁and ▁why ▁effective ▁demand ▁could ▁be ▁def ic ient ▁or ▁excess ive ." ▁ ▁John ▁Stuart ▁Mill , ▁a ▁nin ete enth ▁century ▁British ▁econom ist , ▁also ▁critic izes ▁Mal th us ' ▁Princi ples ▁of ▁Political ▁Econom y . ▁He ▁calls ▁Mal th us ' ▁work ▁" a ▁more ▁m isch iev ous ▁doctrine ," ▁and ▁mock s ▁Mal th us ▁for ▁bel ieving ▁that ▁government ▁inter vention