Board Thread:General Discussion/@comment-11588183-20150501071246/@comment-1298029-20150503215858

Partial transcript of Feige interview mentioned above:

"[Interviewer] You finally referred to one of them as “a [blank] gem” in Age of Ultron. The scepter is the Mind Gem. Do you know what the other ones are? Is it important that you keep that information from us right now, like the Tesseract is the Space Gem, whatever that would be?

''[Feige] Yeah, basically there are two we haven’t introduced yet, but the others are more or less accounted for. ''

[I] Right, but I’m talking about by name.

''[F] It’s definitely the Mind Stone that is now in the Vision. Space, you’re right. Time and Soul are the two that are not accounted for. "''

This directly confirms Vision's Stone as Mind, and Tesseract as Space (see bold sections). We've got direct confirmation from Gunn that Orb is power. Finally, we have the fact that Time and Soul are the only two Stones currently unknown (implied by verbal logic of underlined section). That means that Reality is accounted for, and the only remaining Stone shown is the Aether. From this follows that Aether is Reality; since it is implied by formal logic, it has the same weight as if Feige or Gunn (probably Gunn, as his word probably has less weight than Feige's and you should take the smallest common denominator; even so Gunn's word should be good enough) actually spoke the words "Aether is Reality".