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In general relativity, we think of space and time in spacetime framework. As some people say, metric tensor sign difference, along with our inability to go backward in time suggests that space and time are still substantially different. But general relativity framework itself seems to suggest the spacetime framework.

In non-relativistic quantum mechanics, space and time have distinct difference, or time is rather given as distinct.

So my question is, in light of recent understanding, should we consider space and time separately, or should we think in terms of spacetime?

My understanding has been that it is massive number of microstates in the future that make transition from future to past unlikely probabilistically, close to zero, so things should be interpreted in spacetime framework, rather than distinguishing space and time. But I am heavily confused here too.

Namo Llamas
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    "Should we consider space and time separately" for what purpose? We already do it in classical or quantum mechanics, but it is unpleasant to do in relativistic theories like general relativity or quantum field theory for mathematical reasons. Sometimes we have to anyway, when solving evolution problems. But according to Einstein spacetime is a mathematical fiction, so it is a matter of convenience:"People before me believed that if all the matter in the universe were removed, only space and time would exist. My theory proves that space and time would disappear along with matter". – Conifold Mar 23 '16 at 03:30
  • Namo, would you mind editing your question slightly so that the second part of your question is related to your first question? What do you really mean by the last paragraph and how do you think knowing the first part can help you with the second part? – Benjamin Mar 23 '16 at 04:04
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    Einstein wrote the following in his book Relativity. "Since there exists in this four dimensional structure [space-time] no longer any sections which represent "now" objectively, the concepts of happening and becoming are indeed not completely suspended, but yet complicated. It appears therefore more natural to think of physical reality as a four dimensional existence, instead of, as hitherto, the evolution of a three dimensional existence." – Peter R Mar 23 '16 at 04:15
  • I won't vote to close since it would immediately close your question, but the popularity of questions like this are exactly why I asked What is time, does it flow, and if so what defines its direction?. If you don't think this post adequately addresses you question it might be better to add more to the What is time post rather than answering this one. – John Rennie Mar 23 '16 at 10:20

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