Reasons for 1D Time vs 2D Time: Metrics Explained

[Dmitry67]

Metrics, +++- vs +++--

There are reasons why our space is 3D. In 2D all systems are bound, in 4D they are unstable.

What 'reasons' are for having 1D time vs 2D time? I don't want to go deep into the AP stuff; just may some constraints one might know like 'Maxwell equation won't be consistent' etc.

 

[Dale]

With 2 timelike dimensions you could have closed timelike curves even in flat spacetime. I don't think we would have causality in such a universe.

 

[Dmitry67]

hm, interesting, you're right.
Yes, if there are 2 "times", t and u, then null path can be defined as
s^2 = t^2 where u=0 for example,
which makes lightspeed 'instantaneous' in some directions of time.