If my goal is to talk about something with a particular definition, then I prefer not to use an existing word to refer to it when that word doesn't refer unambiguously to the definition I have in mind. That just leads to confusing conversations. I'd rather just make up a new term to go with my new made-up definition and talk about that.

Well, casual conversation is not the same as using key terms (or words) in a scientific hypothesis, so that's a different subject, but new terms to define new ideas is fine if it's your hypothesis. In conversation, new definitions for old words would be confusing and defining old words in a new way could be confusing as well. That's not what I am saying.

Words can have multiple meanings and the dictionary gives the most popular usages. If we are appealing to the popular use then we still need to define the word. At any rate, whatever key terms that we use in our hypothesis must be precise, unambiguous, non circular, non-contradictory and used consistently throughout our presentation.

Conversely, if my goal is to use the word "consciousness" in a way that respects the existing usage of the term, coming up with an arbitrary definition that is unambiguous and non-contradictory but doesn't respect that existing usage won't quite accomplish that.

I'm saying it is important what EY meant by consciousness. If the person I quoted says we don't know what it is.....then that person doesn't know what the existing usage of the word is, or it is not well defined.

Anyways, why would you use a poor choice of a referent?