There is no uniqueness in cause-effect relation.For example consider the field of medicine.We do have different systems.[i]Ayurveda,[2]Allopathy,[3]Home… Ayurveda the cause of the disease is due to non equilibrium of three VITAL FORCES known as VATHA,PITHA and KAPHA.There are no germs and viruses in this system.But they can cure the patient..[2]Allopathic approach is entirely different.[of course they use modern science to prove there way of outlook] [3]Homeopathy does have its own way of looking at the disease.EVEN in the field of science the cause-effect relation may not look unique.For example what Newton sees for cause of gravitation IS not the SAME as that of Einstein.THEN how one can say that cause-effect relation could be unique?