I didn't say that he wasn't important. I definitely think he's foundational especially to center-left political economics. I just said that nobody is a Keynesian in the original sense anymore. You have to be a neo-Keynesian now.

I think it is safe to say that most of his theories are dead as a doornail. Keynesian thought always had this problem melding macro and microeconomics (similar to physicists have with relativity and quantum mechanics -- the physics of the very large and the very small -- not fitting together).

The stagflation of the 1970s seriously attacked the very foundation of Keynes ideas. It was literally impossible for it to happen. The wage-price spiral was blown to pieces. Even today's world is completely unexplainable in original Keynesian terms, especially when looking at a global scale.

>The stagflation of the 1970s seriously attacked the very foundation of Keynes ideas. It was literally impossible for it to happen

How so? Most of his ideas seem pretty valid. The 70s stagflation was set off by the oil shock when oil prices rapidly increased four fold. I'm not sure how his failure to analyse that happening after his death invalidates that his ideas worked ok under normal circumstances?

Perhaps start here: https://en.wikipedia.org/wiki/Phillips_curve

And the oil shock was sort of a one time thing, and can't be viewed in isolation of Nixon having to close the gold window, more specifically how the US took advantage of the previous fixing of the US dollar price of gold before that fell apart (https://en.wikipedia.org/wiki/1973_oil_crisis#End_of_the_Bre...).

In other words, these were discontinuous and unique things, or turn it around, was it an oil shock, or a dollar devaluation shock? Nothing obliged OPEC to accept less and less value in the dollars they price their oil in.

You could go further and say that the relaxation of these Federal government interventions, including the price and distribution controls on oil and distillates in the '70s, it was pretty much a command economy until Reagan dismantled it, has better allowed the market to function.

(Not that the government has stopped manipulating the money supply, interest rates, etc. ... although that got rather out of control by the end of the '70s as well, with double digit annual inflation and > 20% prime rates to fix that.)

I still have a job seeing what Phillips proposing a relationship between inflation and unemployment in 1958 has to do with Keynes theories of insufficient aggregate demand causing deflation in the 1930s. Keynes's ideas seem pretty good and still relevant, and Phillips' ideas a bit dubious and largely unrelated.

I get the impression much criticism of Keynes is better directed at his followers who called themselves Keynesians and came up with various nonsense after his death than at Keynes himself.

Well, it's just a start, the most (in)famous policy adopted by people who called themselves Keynesian, even got it written into law if I remember correctly, that failed so badly no one can deny the failure. And let's be careful with No True Keynesian arguments....

Plus, unless I'm grossly misinformed, Keynes theories went a lot further than that claimed insight about aggregate demand and deflation, but I haven't studied him deeply, since when I last looked in the '80s it seemed to be garbage, and nothing I've heard since then changes the opinion I formed.

Is the fact that people still vigorously debate whether Keynes is dead reason enough to read him or at least have the basics down?

Keynesianism is in the midst of its death throes.