The musician says reassurance that an independent Scotland will look almost the same as it does now is failing to inspire her and many other Scots.
In an article published yesterday, she said: "Let me declare that this endlessly reiterated sameness scares me.
"I'm horrified by a Scottish version of business-as-usual. It's the opportunity for, and the realistic possibility of, something radically and ethically different from the UK political status quo."
She added: "Let the Yes campaign be positive and hopeful, yes, but let's allow it to be, where it needs to be, angry and bold too, please.
"And let's harness more imagination to the urgent transformative telling of better stories about how we want to live."