Quantum spin liquids are phases of matter exhibiting a variety of interesting properties, such as fractionalization and long-range quantum entanglement. These exotic phases possess a natural description in the language of gauge theory. While most spin liquids studied to date have been described by familiar vector gauge fields, there exists a broader class of stable spin liquid phases described by higher rank tensor gauge fields. In this talk, I will discuss the physics of three-dimensional spin liquids described by symmetric tensor gauge theories. Such theories are notable for their “subdimensional” gauge charges, which are forced to exist in lower-dimensional subspaces instead of propagating freely in three-dimensional space. In some cases, the charges will be fully immobile, in a manifestation of the “fracton” phenomenon. I will review the basic physics of subdimensional particles and their coupling to tensor gauge fields. As an illustrative example, I will discuss rank 2 spin liquids which exhibit the basic properties of emergent gravity. In particular, I will discuss how the fracton phenomenon can be understood as a direct consequence of Mach’s principle.