1) “beyond a reasonable doubt” is a legal standard, not a scientific one.
2) It’s completely outside the bounds of science to “establish truth”. Science only attempts to fashion approximate explanations for our observations. Truth, on the other hand, is an absolute, that we surmise from metaphysical principles is the origin of our observations. An approximation can never equal an absolute, it can only approximate it.
>>An approximation can never equal an absolute, it can only approximate it.<<
Since I am on a grammar roll, that is a tautology.