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I have a question about the paper that haushofer mentioned. In the paper, the author states that

*Moving on to helicity 2, the required gauge symmetry is linearized general coordinate invariance. Asking for consistent self interactions leads essentially uniquely to GR and full general coordinate invariance .*

I am not sure what this means. If we quantize GR, I know of course that we end up with a massless spin 2 graviton. Here, we treat the metric as a quantum field so it is clear that general covariance leads to a gauge symmetry in the quantum theory we obtain.

But let's say with start with quantizing a spin 2 classical field in a flat spacetime. We may have a gauge symmetry which a priori has nothing to do with spacetime coordinate transformation and general covariance. Is the author saying that consistency of a massless spin 2 theory automatically leads to a condition on the spacetime it evolves through? Even if initially the spin 2 particle has nothing to do with a metric? Or am I completely missing the point?

Thanks in advance.