Do you have a source that this is the „correct“ definition? Wikipedia for example uses the definition you think is wrong, and specifically says that CPI measures inflation.
https://en.m.wikipedia.org/wiki/Inflation
I can't get deep links in wikipedia on my mobile browser for some reason, but here's the full page.
The "Terminology" section vaguely references the original Latin word and gives a few nods to when currency was tied to gold. It is a bit hand wavy, though when it talks about new gold supplies being found or later mentions when the cost of money changes, those are both related to the original (correct) definition. Finding more gold increased the money supply, which may change prices though it doesn't have to.
Toman history sometimes covers the idea well as they inflated the currency by minting more coins to increase supply. I can't find a great link at the moment that covers it well from that angle though, I'll try to come back here when I'm at my desk if I find a good link down that rabbit hole.
Am I out of touch? No it is all of modern economists who are wrong.jpg
If physicists decide to reuse the word "meter" for a unit of measuring volume does that mean anyone that uses it as a measure of distance is wrong? Wouldn't it make more sense to create a new term for the new need, a term that doesn't collide with centuries of use?
Perfect question!
In fact, the definition of "meter" has changed over time, and if you stick with the old definition, you'd be off by 0.2 millimeters:
https://www.nist.gov/si-redefinition/meter
Science changes as it needs to. (And the word "science" is doing a lot of heavy lifting here when we are discussing economics, aka the dismal science.)
In my book that's very similar to taking a distance measurement and reusing the word to instead measure a totally different concept, volume. Curious how its different though, I may just be tripping myself up here.
This link does at least acknowledge the original meaning of the word, though it does imply that's an outdated use in economics.
"It is during this period [the era between the mid-1830s and the Civil War] that the word inflation begins to emerge in the literature, not in reference to something that happens to prices, but as something that happens to a paper currency.7"
The footnote doesn't contain any reference.
It's a fool's errand to try to claim the original definition is the "right" or "only" definition at that point.
You've lost this semantic battle against the world, and it's honestly pretty exhausting to see you wasting effort trying to continue fighting a lost cause.
Monetary inflation is an important concept that is now almost entirely ignored. An increase in the cost of goods can be interesting, but its a second or third order effect of an extremely complicated system.
Price changes are meaningless without context and extremely difficult to understand with context. Money debasement, or inflation, is easy to understand and is a primary input to the system rather than a downstream effect.
Historically, monetary inflation and consumer inflation coincided (Supply of X goes up -> X is devalued -> consumables are now charged at higher X), and so distinguishing between the two wasn't particularly pertinent.
The Roman Empire's observations that debasement of their coins resulted in the increase in prices, meant that the original conception of inflation really was as a monetary phenomenon, not just that prices are going up.
It's really only a relatively recent phenomenon, from the early 20th century, that you had dual definitions trying to occupy the same word, although the concept that price inflation could deviate from monetary inflation probably was starting to be understood with the establishment of price indices in the 19th century.
Keynes arguing that prices could rise independent of the monetary supply post-Great Depression increased the focus on consumer inflation. It was around the 1970s where inflation more commonly came to consumer inflation in academia. 'Stagflation' of the 1970s is probably the tipping point in usage.
To conclude: it's not really wrong to use inflation to refer to monetary inflation, as it's the original usage, but considering consumer inflation as 'inflation' is definitely more in fashion (especially in the US).