The Tradition of Formal Inquiry declares that among equally valid explanations, the one with the least assumptions wins. And he who needs the additional assumption gets to defend it. The burden of proof rests with the claimant.
Especially on one as bizarre as this, the claim to an: ‘Independent and Separate Observer, Self, Subject’. But we shall not quibble. And we shall not whine.
This Parsimony Principle goes back to before Aristotle in the Western Tradition. The most recent variant is ‘Occam’s Razor’, very popular with intellectuals who revel in obscure Latin inserts: Entia non sunt multiplicanda praeter necessitatem.