1. a negative relationship between income and consumption, other things being equal (we found that in (Chyi & Yang, 2009, link to PDF on this page) and in a forthcoming book chapter using Pew 2008 data) — this is based on the classic economic definition.

If #1 is true,
2. there must be a substitute that is considered “better” by users, other things (e.g., price and content) being equal.

So I think any inferior good (by economic definition) has substitutes.

And yes, my inferior good can be your normal good. (Rice, for example, has become an inferior good in wealthier Asian countries.)

-DO inferior goods exist?
-How should one interpret them, Are they inferior to other goods or are they just inferior.
– Can a good without substitutes be inferior.
– Is it not possible for a good we call “normal” to be inferior on other consumers given their income endowment.

My hypothesis is that every good has a potential of being an inferior good based on consumers’ initial income and their preferences.