Interesting. Thanks for clarifying that.

Regardless of if "I" is a valid index in this case though, certainly "person P used the word 'I' and concluded 'I am in a blue room' " is a valid predicate, even if person P's use of "I" was gibberish.

We can then say that 99% of people, if they concluded that gibberish, would have gone on to conclude the gibberish, "I was, in fact, right to conclude that I was in a blue room."