Probability  test is the only testing measurement available to a judge while appreciating an evidence on the anvil of relevance.
 Admissibility of evidence has been made discernible through various acts and conditions precedent or condition subsequent and this area has fewer grey areas that bites the conscience of a judge or confuses the litigants or the  legal service provider. 
But then to interpret a fact through probability test has not been fixed and still to-day even the Apex Court Judges could not rise above subjectivity. The gender bias , religion bias, caste bias, region bias, class bias, caste bias, scale bias and even political bias is visible every now and then.
Judges are human being. These biases shall always be there either in this form or that, either in this quantity or that; but that pre-occupiedness shall be there and cannot be ruled out completely..None can claim perfect immunity or objectivity.