So aliens, or alternate Newtons, or just Tegmark duplicates of Newton, may all have discovered gravity before our Newton did—if you believe that “before” means anything relative to those kinds of separations.
If by “before” you mean ‘in the past light cone of’, I wouldn’t be that surprised if nobody had discovered gravity before our Newton did.
If by “before” you mean ‘in the past light cone of’, I wouldn’t be that surprised if nobody had discovered gravity before our Newton did.