This discussion has come up more than a few times on this forum, so I recently had the opportunity to ask Michael Turner (well-regarded general relativist) after a lecture whether time should be treated as a coordinate or whether time should be treated as a dimension.

He asked me what I meant by the these two terms. I said that by dimension I meant the ability to move about (i.e., time travel) and by coordinate I meant solely something that identifies a position within a frame of reference (i.e., no time travel since no future exists by which to travel to).

He then answered the question: time should be treated as a dimension.

Harv

• Harvey, did you ask him HOW to move back and forth in time then? - alexander - January 8, 2002 - 15:58 UTC
  • No, I didn't ask that - harvey1 - January 8, 2002 - 16:00 UTC
    • Well, then it is just his unsubstantiated opinion then. - alexander - January 8, 2002 - 16:08 UTC
      • Actually, I lean in this direction - harvey1 - January 8, 2002 - 16:36 UTC
        • This is why - luis_hamburgh - January 10, 2002 - 00:24 UTC
          • I have some issues - harvey1 - January 10, 2002 - 05:59 UTC
            • Is space or time physical anyway? - alexander - January 10, 2002 - 21:13 UTC
              • I'll ask you what I asked Luis - harvey1 - January 10, 2002 - 21:39 UTC
                • We know that experimentally (that nothing depends on location), - alexander - January 10, 2002 - 23:58 UTC
                  • This is a different statement - harvey1 - January 11, 2002 - 03:49 UTC
                    • please explain symmetry transformation calculations again... - quiet - January 11, 2002 - 07:10 UTC
                      • There should be plenty about symmetry in physics on Internet. - alexander - January 11, 2002 - 21:36 UTC
                        • Physicist weighs in about history, religion but not Relativity - quiet - January 11, 2002 - 22:59 UTC
              • WE HOLD THESE TRUTHS TO BE SELF-EVIDENT - quiet - January 11, 2002 - 01:57 UTC
            • Sloppy response for Harv - luis_hamburgh - January 11, 2002 - 01:00 UTC
              • Well, let's clarify my position - harvey1 - January 11, 2002 - 03:40 UTC
                • E-Prime - luis_hamburgh - January 12, 2002 - 16:08 UTC
              • You guys....living in the real world, does that make sense? - quiet - January 11, 2002 - 07:16 UTC
      • Your saying.. - bruce - January 9, 2002 - 01:56 UTC
    • By the way, Harvey, do you have his e-mail or sort? - alexander - January 8, 2002 - 16:12 UTC
      • Sorry - harvey1 - January 8, 2002 - 16:39 UTC
    • Time travel into the future... - bruce - January 9, 2002 - 00:57 UTC
      • Thanks Bruce - harvey1 - January 9, 2002 - 14:55 UTC
        • You seem to know a great deal about rhetoric - quiet - January 9, 2002 - 22:17 UTC
        • No - bruce - January 10, 2002 - 01:54 UTC
          • It was unbelievable - harvey1 - January 10, 2002 - 04:56 UTC
• Bruce - bruce - January 9, 2002 - 00:49 UTC
• Thank you, Harv (nt) - luis_hamburgh - January 10, 2002 - 00:02 UTC