Not necessarily, because functionalism where the substrate doesn’t matter can be viewed as a form of dualism. Particularly if we’re talking about animal intelligence and mind uploads. You can see the more extreme forms of this sort of dualism in sci-fi when minds are swapped between bodies, or someone’s mind is transferred to a computer or robot.
Also, dualism doesn’t require supernaturalism. It just requires there be more than one kind of fundamental stuff. There’s no logical principle saying nature has to be only one kind of substance or process. Many modern philosophers who are dualists are also naturalists. Chalmers for example, is a property dualist regarding conscious states (qualia).
Also, one can be a neutral monist, believing that mind and matter emerge for a neutral substance that is neither. Maybe a Kantian would defend something like that? Anyway, philosophy has many options regarding dualism, mind and matter which aren't supernatural. You can even be an idealist and a naturalist. You just think the physical world is material ideas in minds.
Also, dualism doesn’t require supernaturalism. It just requires there be more than one kind of fundamental stuff. There’s no logical principle saying nature has to be only one kind of substance or process. Many modern philosophers who are dualists are also naturalists. Chalmers for example, is a property dualist regarding conscious states (qualia).
Also, one can be a neutral monist, believing that mind and matter emerge for a neutral substance that is neither. Maybe a Kantian would defend something like that? Anyway, philosophy has many options regarding dualism, mind and matter which aren't supernatural. You can even be an idealist and a naturalist. You just think the physical world is material ideas in minds.