You've obviously never heard of how Compass Plants and Sunflowers work. They reach a maximum heights (about 7-8 feet), and without growing any larger, will point at the sun at all times during the day. Even when it's cloudy. Explain THAT with auxins.
And besides, we can explain our nervous system with chemical reactions and elecrical impulses. Just because it's mechanically logical, doesn't make the reality of it any less profound.
Again, no one's answered yet why we should even care if plants or animals feel pain. We use them as tools, nothing more. Even our pets are tools... or maybe I should say toys.
