Most of us take it for granted that there are three dimensions, perhaps four if we count time. But for over 200 years, mathematicians and scientists have proposed further dimensions. In some standard versions of contemporary physics eleven dimensions are now proposed. But might the notion of additional dimensions be an empty idea that derails physics? Critics like Nobel Laureate Richard Feynman argued that proponents of extra dimensions "cook up explanations" for what we can't observe. And from Kaluza-Klein particles to microscopic black holes, CERN researchers admit that no empirical evidence for extra dimensions has ever been, and more importantly perhaps could ever be, discovered.

Should we see reject talk of higher dimensions as speculative fantasy, good for sci-fi movies perhaps but not for scientific theories of the universe? Would we be better off seeing extra dimensions as a mathematical tool rather than a description of reality? Or might our mathematical hypotheses of multiple dimensions in fact describe the essential character of the world?