The claim consciousness would have been detected.

It keeps being claimed (eg David Papineau, Sean Carroll et al) that if consciousness caused anything in the brain over and above physical causation, then neuroscientists would have detected it by now.  I have no idea why they would think this.  The initial change precipitated in the brain might only have a minute effect, but then, via physical chains of causes and effects, cascade to larger and larger effects (see the video). Since neuroscientists are materialists, they won't be looking for any such influence and our functional MRI's lack the resolution to make any assertions in this regard in any case. It's just silly nonsense that materialists constantly put out.

Note that the notion that the world is physically closed is incoherent in any case.  I argue this in my other blog in my A Causal Consciousness, Free Will, and Dualism.