 (1)–(5) use the concepts of the mental and the physical (or of corresponding laws) to specify the notion of neutrality. Since the mind/matter distinction can be drawn in different ways, the notion of the neutral will vary accordingly. And if the mental and the physical are defined as complements of each other, thereby ruling out the possibility of entities that are neither mental nor physical, then there cannot be any neutral entities (at least in the neither sense of the term).