What about jellyfish or oysters? They don't have a brain and have very limited sensory and movement abilities. If they have an unconscious then why not carnivorous plants?
Until the definition, and underlying semantic assumptions, are clear, don't build too many linguistic castles on top of it.
Modded into invisibility, looks like you violated one of the sacred tenets of Hacker News :)
Though I do notice a lot of innocuous comments get down-voted, for some reason. I wish there was more to hold down-voters to account for unreasonable mods..