However, it is quite clear that if beans have spirits, they are distinctly malevolent ones.
Fat Marrow–if your GF does it, quietly agree with her.
If she does not do it (wink-wink-nudge-nudge), dump her.
But irrational beliefs cannot be reasoned out, 'cause they weren’t reasoned in, in the first place.
Just a nitpick. Reflex implies a nervous system.
Don’t compost piles emit methane? Would your girlfriend suggest that a compost pile is a sentient being? What about a half of a compost pile? How about just a piece of a radish? I don’t think the argument is very strong.
So, are underground gas deposits sentient beings? Are oil refineries sentient beings? Are chemistry labs sentient beings?
While it may be true that all farts include emissions of methane, it is certainly not true that all emissions of methane are farts. That your girlfriend did not come to realize this on her own makes me think she’s incredibly stupid. Sorry.
Have her read this thread.
I really have nothing to add but this does remind me of a great Jack Handey “Deep Thoughts” quote:
"If trees could scream, would we be so cavalier in cutting them down?
Well… we might, if they screamed all the time, for no good reason".
Sex organs from a dead plant! You shouldn’t have!
Old WKRP bit:
Johnny: In the spirit of Christmas, we killed a tree for you.
Thank you all for your responses and for your your recommendations, but I will not be dumping my girlfriend on account of her illogical and irrational beliefs!
It was her idea to post this question as she thought you’d all prove her correct so thanks for showing her up on that front!
Chronos you were correct with the circular agument point. This one just goes down to her hippy tendencies that I can quite easily live live. Just wanted to appease her by posting the question to some rational and logical folk. I’m glad one of my posts has finally sparked debate!
Still, if she doesn’t put out, you should dump her anyway. 
“Don’t you like flowers?”
“Sure I do --I like children, too, but you don’t see me cutting their genitals off and sticking them up around the house.”
W.C. Fields? Groucho Marx? Winston Churchill? I forget. A good 'un, though.