GRAVITY PROBLEMS -- off topic from {Falsifying a young Universe}

You appear to be asking a metaphysical question, and seeking a metaphysical answer.The proper answer is that science does not do metaphysics. A scientific explanation has to do with making reliable predictions.Kant said that we cannot know the world in itself. We can only know the world as it appears to us. Or, in other words, there cannot be an answer to metaphysical questions. I am inclined to think that Kant was correct.

Your analogy is poor. But I will stretch it a little in the hope of clarifying the role of math.There are lawyers who try cases (the trial lawyers). There are other lawyers to win election to Congress and to the senate - let's call those legislative lawyers.The work of the legislative lawyers is fully integrated into the rules by which government operates. The work of the trial lawyers is more of an add-on as needed.The role of mathematics better fits that of the legislative lawyers. It is fully integrated into the scientific methodologies of the astronomers and cosmologists. It isn't merely the kind of add-on trial lawyer aspect that you think it is.

Let's not try to carry this analogy too far.My point was simply that the mathematics is built into the methodology, so it cannot be dismissed as simply as you would like. If you want to criticize the methodology, then you first need to learn a lot of astrophysics, so that you can understand fully what you are wanting to criticize.

I'm not sure what you take to be the core assumptions.As I see it, the core assumptions for astrophysics are:

• Measurement systems that work locally can be extended to apply throughout the cosmos.
• The behavior of light appears the same to all observers.

The mathematics, including GR, arises from those assumptions.