> If Mathematica is intended to be suitable for mathematical research, then its source must be open so that the results are auditable
You don't need source to audit the results. It's a tool, just like a calculator or a table of logarithms or a table of integrals. If I use an HP calculator for a calculation, for instance, you don't audit my results by examining the source for the calculator's firmware and convincing yourself it is right and then accepting my results. No, you audit my results by doing the calculation on your Casio calculator and seeing if it comes out the same.
You don't need source to audit the results. It's a tool, just like a calculator or a table of logarithms or a table of integrals. If I use an HP calculator for a calculation, for instance, you don't audit my results by examining the source for the calculator's firmware and convincing yourself it is right and then accepting my results. No, you audit my results by doing the calculation on your Casio calculator and seeing if it comes out the same.