Newton's Laws of gravity had no conditons for a couple hundred years. They were considered to be part of God's design.
I still consider them such. In Newton's day we had no power to look into those regions where they did not apply (the very small, black holes, etc.) They are still invariably true for everyday conditions. We have only had the power to test General Relativity and the Einstein's THeory of Gravity for a single generation. Who is to say that they won't be confirmed beyond doubt in a 1,000 years?