Sentience seems like a standard that’s an outgrowth of our own human biology and experience of the world. It feels like we value sentience because it’s what we have; and while plants aren’t sentient, they do have nervous systems and perceptions of sorts.

I know that “save the plants, man” is a position that’s easy to ridicule, but they’re very literally our bodies and our breath, and as such I believe they should be afforded respect.

If you’re interested at all, Plant-thinking: A Philosophy of Vegetal Life is a book that’s informed my thought on this.