They must prove mindlessness subsumes consciousness.
Unfortunately, IMHO, this truth would invalidate truth.
I think you must prove this is necessary. Necessary for what?
I am not defending the atheist position, but whatever one seeks to prove must begin with the facts, that is, with the way things are. Well, the way things are is a real perceiveable material universe, with real material living organsims, some of which are conscious, and some of which (though much fewer) are volitional beings, required to live by conscious choice, which requirement makes knowledge and reason both possible and necessary.
Since conscious rational volitional beings are here in the materially existent world, it is obvious they are possible to such a world. Why is there any necessity to demonstrate the exact method by which they got here. And exactly how do you know they weren't always here?
Hank