Original sentence: Homeopaths contend that the lack of definite predictions by the law of similars makes it difficult to test scientifically.Homeopathy does not assert that there is a way to determine definitively an effective remedy for a patient; homeopaths will often disagree on the best one in any given case
Edited sentence: The lack of definite predictions by the law of similars makes it difficult to test scientifically.There is no certain way to determine an effective remedy for a patient, and homeopaths will often disagree on the best one in any given case