Evolution

[vulcanlogician]

So, you are making me channel my inner Thoreau here: why aren't plants conscious? I cannot confidently say they aren't. If pressed, I'd have to conclude that they have a "nub" of consciousness--aka a basic system of sensory response.

There's nothing basic about their sensory response.  They're the lords of organic chemistry.  We'd be the relatively impoverished ones in that comparison, even as we're the ones that seem overflowing with the other thing, consciousness.

Right. I want to make it clear that I'm not saying plants have a consciousness similar to ours. I'm merely asking if they have consciousness at all-- since they obviously respond to stimuli, albeit slowly.