This is an argument for agnosticism. All else being equal it would be just as presumptuous to postulate the existence or non-existence of an entity. But I thin

This is an argument for agnosticism. All else being equal it would be just as presumptuous to postulate the existence or non-existence of an entity. But I think that the arc of history would suggest that all things are not equal. We do after all know a thing or two about consciousness even if a clean definition eludes us (we also don't really have good definitions for lots of things so maybe finding definitions is not the more urgent goal of philosophy). It was less than 100 years ago that vitalism held sway in the philosophy of biology. We find a similar state in the study of mind. You can still postulate the existence of something like the soul, but I think it is increasingly hard to say that this thing is not generated by matter as people once said.