There is no testable alternative explanation.
And the bio-electro-chemical model is
testable, & has yielded fascinating results.
I’m not suggesting an alternative model. I’m saying that a purely physical explanation of the mind is by definition incomplete. You cannot reduce that which is mental entirely to the physical, without losing something vital - the experience of being aware, of looking out from within, at a world we perceive in our minds.
The reverse is also true btw. While we cannot even conceive of the existence of the brain and it’s functions independently of the mind (because it is in the mind, and only in the mind, that conceptions are manifested), to reduce the physical to the mental, as idealists do, is to completely abandon external, mind-independent reality. Thus we slip into the intolerable despair of solipsism.
So we arrive at the point where mind and body, consciousness and objective physical reality, are interdependent. But these two cannot ever be entirely reconciled, nor can the thinking person ever be at ease in the material world, without developing a conscious awareness of the spirit.