Ausgehend von einem Artikel von Brad DeLong hat sich eine interessante Diskussion entwickelt, die unter anderem Fragen wie –  Ist VWL überhaupt eine Wissenschaft? Sind Argumente von Fama et. al. das Äquivalent zur Theorie der Kreationisten? – berühren. Ein meiner Meinung nach bemerkenswerter Kommentar ist von Jacques René Giguère:

Astrophysicists might disagree on string theory, they don’t argue that the universe doenn’t exist…
What Fama and others do is willfully forget Keynes central insight: a money economy is totally and fundamentally different than a barter-goods-only economy.
In a barter-goods economy, you can have exchange,specialisation of labor, saving, investment, technical progress, almost anything you want. You can have a starvation causing-drought and you all die. You can have a recession if you stop working and the guy you traded with is forced to stop producing while he adjust his specialisation.
But the one thing you just can’t have is a depression. The real meaning of Say’s law is that saving implies producing an equivalent good which is then invested as inventory, therefore causing no fall in aggregate demand. In a goods-economy, you just can’t get a race to liquidity.
An economist not knowing that difference is worse than a biologist not knowing evolution. It’s a biologist not knowing the difference between an animal and a rock…and being proud of it.