Abstract

The position called Moderate Ontic Structural Realism, presented by Michael Esfeld and Vincent Lam, is described and criticised. Three theses are proposed. First, that the regarded position is intertwined with treating Spacetime as a property (or aspect) of the gravitational field. Second, that the metaphysics of properties used in Moderate Ontic Structural Realism leads to unfortunate consequences such as abandoning the equality of heuristics of constructing representations of gravity in General Relativity. Finally, the third thesis is that Spacetime should be interpreted metaphysically as part of a wider gravitational structure.
After a summary of Esfeld’s and Lam’s position , reference to the issue of the equality of heuristics is presented as a critical perspective. A criticism of Moderate Ontic Structural Realism is formulated and further postulates about the ontology of Spacetime are proposed. In conclusion, an answer to the question stated in the title is suggested: spacetime is a part of the structure.