Deflation and inflation are very tricky terms.

While Weimar Germany was experiencing hyper-inflation, they were in a deflationary spiral. Few people realize that hyper-inflation can come about just as easily in a deflationary environment as an inflationary environment.

A country can be experiencing inflation of prices while their country is in deflation. It all depends on balance of trade and what other currencies are doing in relation. In a world economy, the price of imports (other currencies) matter.

In Weimar the price of things were so high people could barely or not even afford common daily needs. Yet some non essentials were dirt cheap. Anything that could be sold for any price to buy food and needed stuff. A grand piano could be had for a very cheap price measured in loaves of bread yet for a high price (compared to an earlier time period) measured in a currency that was rapidly loosing its purchasing power. Yet someone from abroad could buy either the loaf of bread OR the piano for almost nothing if they had "good" currency that was not loosing its value. So even in a hyper-rinflationary environment there was both inflation and relative deflation of prices (depending on the measuring device) within the country yet a severe deflationary spiral when viewed with a measurement of values outside the country.

So it is not a cut and dried, everything goes up in inflation or everything goes down in deflation, nor even a cut and dried of the view if it IS inflation or deflation. It all depends on the measuring stick and in a world of floating fiat currencies with no bench mark and no anchor, it is very hard to even come up with a bench mark.

As far as getting your information and opinions from an economic historian, beware. So much current economic "history" has either been written or re-written by a group of economists with a Keynesian point of reference. I have found that some of the economic historic explanations are no better than the person interpreting them. I think we have been sold an economic bill of goods that sometime in the not to distant future will become evident it was an incorrect paradigm. Models are only as good as the assumptions going into them. If the model is off, the predicted outcome will be off.

History is usually recorded by the victor of the war. It is often a slanted historical perspective and rarely accurate. In this case the victor of the economic war was Keynes, and I think a lot of the historical explanation around that war is biased at best and completely inaccurate at worst. And in fairness to Keynes, they only pulled out and used the portions that fit their agenda and bias. And ignored the really smart stuff he said, which amounted to quite a bit..

John