Theists and atheists usually disagree about whether human beings are natural entities, but agree that human beings are persons.  Christians and other theists generally believe that human persons are composed of a physical entity (a physical body) and supernatural entity (a soul).  Atheists generally don’t believe in souls or other supernatural entities, so most atheists are naturalists who believe that there are physical entities that are persons, and thus that there are natural entities that are persons.  This combination of metaphysical categories should be retained not because it is obvious that naturalists are correct, but simply because it would beg the question in favor of theism and supernaturalism  to eliminate this combination from the start.

I see this as similar to the reason for retaining the combination of epistemological categories known as synthetic a priori.  A key question in epistemology is whether there are such a things as synthetic a priori truths.  So, in epistemology, you want to start out with a categorization of truths that includes synthetic a priori, and then arguments and debates occur in epistemology to determine whether  this combination of categories is coherent, and whether there are any such truths.  

Similarly, you want to start out with a metaphysical category of natural entities that are persons, and thus allow arguments and debates to occur in metaphysics to determine whether this combination of  categories is coherent, and whether there are any such entities.

If God exists, God would be a paradigm case of a non-natural entity that is also a person.  Ghosts, angels, and demons would also be examples of non-natural entities that are persons.  Naturalists deny the existence of non-natural persons, especially the existence of God. But not all naturalists believe that the sentence ‘God exists’ is logically incoherent.  Many naturalists believe that the existence of God is logically possible, but that there is in fact no such being.  

Some atheists believe, for example, that the idea of a ‘non-embodied person’ contains a logical contradiction, but other atheists believe that the idea of a ‘non-embodied person’ is coherent; they just think that there are in fact no such persons. 

In any case, since theists are committed to the existence of non-natural persons, it would beg the question against theism to eliminate this combination of categories from the start.  Theists need to present arguments in support of the coherence of this combination of categories, and atheists and  naturalists need to argue either for the incoherence of this combination or else for the view that there are in fact no such

persons.