Multiple time dimensions

The possibility that there might be more than one dimension of time has occasionally been discussed in physics and philosophy.

Physics

Special relativity describes spacetime as a manifold whose metric tensor has a negative eigenvalue. This corresponds to the existence of a "time-like" direction. A metric with multiple negative eigenvalues would correspondingly imply several timelike directions, i.e. multiple time dimensions, but there is no consensus regarding the relationship of these extra "times" to time as conventionally understood.

Nonetheless, theories with more than one dimension of time have sometimes been advanced in physics, whether as a serious description of reality or just as a curious possibility. Itzhak Bars's work on "two-time physics"[1], inspired by the SO(10,2) symmetry of the extended supersymmetry structure of M-theory, is the most recent and systematic development of the concept (see also F-theory).

Philosophy

An Experiment with Time by J.W. Dunne (1927) describes [2] an ontology in which there is an infinite hierarchy of conscious minds, each with its own dimension of time and able to view events in lower time dimensions from outside. His theory was often criticised as exhibiting an unnecessary infinite regress.

The conceptual possibility of multiple time dimensions has also been raised in modern analytic philosophy.[3]

The English philosopher John G. Bennett posited a six-dimensional Universe with the usual three spatial dimensions and three time-like dimensions that he called time, eternity and hyparxis. Time is the sequential chronological time that we are familiar with. The hypertime dimensions called eternity and hyparxis are said to have distinctive properties of their own. Eternity could be considered cosmological time or timeless time. Hyparxis is supposed to be characterised as an ableness-to-be and may be more noticeable in the realm of quantum processes.

The conjunction of the two dimensions of time and eternity could form a hypothetical basis for a Multiverse cosmology with parallel universes existing across a plane of vast possibilities. The third time-like dimension hyparxis could allow for the theoretical existence of sci-fi possibilities such as time travel, sliding between parallel worlds and faster-than-light travel.

While Bennett has put forward some curious speculation, his ideas stop at some subjective aspects of the perception of time which does not place them on a fully scientific basis. The question of measurement, how one would measure these hypothetical extra time-like dimensions, is left unaddressed.

In fiction

The Number of the Beast by Robert A. Heinlein (1980) features a six-dimensional cosmology in which there are three time dimensions, denoted t, tau (Greek τ) and teh (Cyrillic cursive т).

The Ware Tetralogy by Rudy Rucker features aliens called Metamartians who "are from a part of the cosmos where time is two-dimensional".[4]

In Diane Duane's Star Trek novel, The Wounded Sky, the Hamalki physicist K't'lk states that time has three dimensions, called "inception," "duration," and "termination."

See also

• Dimension
• Hyperspace
• Space-time#Privileged_character_of_3+1_spacetime

References