|From heart beats to the biochemistry of DNA, rhythms of symbol handling are essential to biology. To describe the rhythms of symbol handling, a new kind of physics is required. Acknowledging the agents that handle symbols leads to what could be called “two-clock physics”―or a “physics of the unexpected,” in contrast to traditional physics which has exclusively focused on one-clock physics.Two-clock physics puts physics into the same evolutionary context as biology. From the point of view of two-clock physics, rhythms of agents transmitting symbols are not arbitrary motions to measure with respect to a given coordinate system with a time variable. Instead, these rhythms, once mathematically expressed, form a base structure, on top of which concepts of space and time become optional assumptions. Characteristic of the base structure is a form of synchronization, distinct from that introduced by Einstein in special relativity, and requiring that agents respond to unpredictable effects.For problems of biological rhythms, including those associated with the exercise of mentality, two-clock physics, introduced here, offers biologically appropriate alternatives to the usual concepts of space and time.