scientific

In this age those who question the hadith say: "This hadeeth is contrary to the principal of scientific research, that fly is the main cause of disease transmission, then how is it possible in the fly there is a medicine (bidder) it? They forget that most of the scientific problems they make of proposition are nothing but theories, how many theories say something that is true today, and then after a while, both long and fast, it turns out to be wrong