Keynes y los clásicos

Keynes,  arrollado por los Nuevos  Clásicos (R. Lucas) y los Neokeynesianos (Mankiw). Las cosas que se tiraron a la basura. (Skidelsky en "Keynes: The Return of The Master")... Y que la crisis ha vuelto a revivir. El punto (1) me parece el más importante. 

Mainstream economics today, by improving on the maths, and abandoning common sense, is further away from Keynes’s economics than ever before. Eight differences stand out:

(1) Keynes’s distinction between uncertainty and risk has been abolished. All uncertainty about future events can be reduced to a probability calculus –that is, to the presumption that the probability distributions of the past and present are also valid in the future. This amounts to saying that economic agents have perfect information about future events or, in weaker versions, that perfect information is available, though costly to obtain. Keynes’ser marvellous insights into the psychology of financial markets, the variability of investment, and the role of money as a store of value are irrelevant.

Quizás no toda la diferencia resida ahí, pero seguro que estos elementos se han desechado por no er susceptibles de entrar en un modelo matemático. 

 (2) New Classical economics has abolished time. Events do not have to happen in a sequence: they happen simultaneously. Equipped with continuously updated information, economic agents adjust instantly and efficiently to all external ‘shocks’. The New Keynesian economists inhabit the same mental universe, but, by ‘relaxing the assumptions’, they allow for situations in which markets may misbehave in the short run. Although real GDP fluctuates around a rising long-term trend, there may be short-run fluctuations primarily caused by ‘stickiness’ of prices in face of demand shocks, and they have investigated the microeconomic sources of this stickiness. Even so, their models cannot explain the sources of aggregate demand failure, which require a recognition of uncertainty. Keynes said that people cannot possess the information required to validate the theory that markets are self-equilibrating at full employment either in the long run or in the short run. 

(3) While the simple aggregate equations of Keynes’s macroeconomic model are still taught, there has been a return to neoclassical standards of method. No longer is it acceptable to posit ad hoc supply and demand functions. Macroeconomics is best seen as an application of microeconomics, in the sense that macroeconomic models should be based on optimization by firms and consumers. This is contrary to Keynes, who believed that individual behaviour is structured by aggregate psychological data (‘propensity to consume’, ‘state of confidence’, ‘liquidity preference’) arising from inescapable uncertainty about the future. 

(4) Mainstream macroeconomics today is based on supply, not demand. It has reasserted some version of Say’s Law –that supply creates its own demand –which Keynes repudiated. Thus, both New Classicals and New Keynesians believe that the growth of real GDP in the long run depends on an increase in the supply of factor inputs and technological progress. Further, many economists only accept sticky contracts as contingent, not inescapable. The ‘supply-side’ school of economists has been busily advocating their dissolution by weakening trade unions and fixed-wage contracts and stiffening conditions for receipt of unemployment and welfare benefits. They look forward to a world in which all contracts are instantly renegotiable. 

(5) Contemporary mainstream economists have reasserted the quantity theory of money –the view that the rate of growth of the money supply determines the rate of inflation –completely in line with Friedman’s argument, but contrary to Keynes, who asserted that this is true only at full employment. 

(6) In modelling economies, contemporary macroeconomists are not fazed by the unrealism of their assumptions; indeed, they regard this as a strength of their models. Fortified by maths, they have reverted more completely than their ancestor classical economists to ‘ideal-type’, or Platonic, theorizing, sacrificing truth for mathematical elegance. This is in direct contrast to Keynes, who insisted on ‘realism of assumptions’. 

(7) In contrast to the Keynesian consensus during the ‘golden age’, it is now widely thought that governments should not attempt to fine-tune the economy. Instead, stabilization policy should merely aim to assist the market’s self-correcting capabilities, chiefly by keeping prices stable. 

(8) Whereas in the 1950s and 1960s stabilization was seen as a control-theory problem, it is now modelled as a strategic game between the authorities and private agents, whose expectations the authorities need to ‘manage’ by means of clear rules. This follows the normative prescription that governments should aim to provide agents with a consistent model of the economy. This is expected to make real variables more stable.