Representational Adequacy, Natural Selection, and Quantum Ontology: Against a Three-Dimensionally Spatial Reality

We human cognizers represent reality as three-dimensionally spatial. However, despite appearances to the contrary, I contend that the likelihood that reality is three-dimensionally spatial in accordance with our spatial representations is either low at worst or inscrutable at best, if these representations are the results of evolution. The key reason is that natural selection is interested primarily in fitness and not specifically in truth per se. Dimensional veridicality of our spatial representations — i.e. the property of veridically representing the true dimensionality of space — is not required for adaptive behaviour. Dimensional veridicality per se confers no additional evolutionary benefits. Representational adequacy with respect to the relevant structure of reality suffices for evolutionary fitness without dimensional veridicality. Independent considerations of quantum ontology — e.g. wave function realism — also challenge the common view that reality is three-dimensionally spatial. There are serious considerations that counsel agnosticism: we do not know, and hence should suspend judgment about, the true spatial dimensionality of reality.