Talk:Background independence

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Article claims, "Below is given an easy argument which uses only the very basics of GR making it accessible to anyone..."

Come on. I mean, really.

[edit] Does emergence itself signify a concept of time

The wording of the article "independent of the actual shape of the spacetime and the value of various fields within the spacetime, and in particular to not refer to a specific coordinate system or metric" seems to me careful and important. I contrast it with writing that seems to suggest that the idea of time is absent from the theory.

For example, in the glossary of his book "The Fabric of the Cosmos," Brain Greene gives this entry for background independence: "Property of a physical theory in which space and time emerge from a more fundamental concept, rather than being inserted axiomatically." In the text (p.487) he writes, in relation to applying this concept to string theory, "In this proposal, concepts of space and time fail to have meaning until innumerable strings weave together to produce them."

What Greene writes seems very problematic. How can we conceptualize anything to "emerge" from something else without some time-like dimension along which change takes place? How can we conceptualize the difference between before and after the "weaving together of innumerable strings" without that difference taking place over something like a dimension of time? It seems to me that such questions signify that the idea of a time-like dimension is contained in the theory ab initio, but not a specific metric. And it seems to me that the formulation in the present article takes this position. Doe this reading have merit? jjb 00:09, 11 February 2007 (UTC)