In response to this question, Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
The question needs a detailed answer, but I would briefly state the following:
Not everything reported as hadith is considered a hadith from the Prophet (peace and blessings be upon him). Hundreds of scholars have worked diligently to establish a scientific methodology of sorting and authenticating the traditions that can be safely attributed to the Prophet (peace and blessings be upon him). One of the principal criteria for verifying hadith is that it should not contradict reason or empirical facts.
Another criterion is that it must not contradict the fundamental principles established by the Qur’an and authentic Sunnah.
Thirdly, in order for a hadith to be acceptable, it must have been reported and transmitted through a reliable chain of transmission where every link is known and reliable.
Having said this, we must guard against dismissing certain traditions which may appear to be contradicting reason while on a deeper study it would be found that it is our interpretation that is wrong, not the hadith itself. This often happens in regards to matters where human reason cannot operate, namely, that which is related to matters of ghayb (Unseen). As believers, we must believe that this area of reality is not accessible to reason or empirical knowledge. The only avenue for this knowledge is revelation from Allah. The Prophet (peace and blessings be upon him) received inspirations other than the Qur’an regarding such matters, which is often related in the Hadith.
So we do not rush to conclude that all hadiths are fabricated. And also we must never attribute falsehood to the Prophet (peace and blessings be upon him). By having doubt about the Prophet (peace and blessings be upon him) we are rejecting the entire Qur’an as well.
Dr Sano Koutoub Moustapha, professor of Fiqh and Its Principles, International Islamic University, Malaysia, adds:
There are differences between them in terms of their authenticity and authority. The whole Qur’an is known to be definitive and free from falsification and forgery, while the Sunnah is divided into definitive and speculative. The former is authentic and free from any falsification, while the latter has been subject to falsification and forgery. But, unless a Hadith is proven to be unauthentic, we have to believe in it and accept it.
As for the claim of having many hadiths contradicting scientific realities, I shall say that there is no such authentic hadith at all. Meaning, if a Hadith is found to be in contradiction with scientific realities, this hadith must be a false one or the so-called scientific reality is not, in fact, a reality. Therefore, one will have to conclude that the contradiction will never occur between an authentic hadith and a scientific reality, and if there is any contradiction, it must be because of a misunderstanding of either the revelation or the scientific reality, or both of them at the same time.
Based on this, I would like to confirm to our beloved brothers that there is no contradiction between an authentic hadith and Qur’anic verses or scientific realities. Further, I would also like to clarify to him that the Prophet Muhammad (peace and blessings be upon him) never said any hadith to suit his own needs. His actions are considered to be an application of the meaning of the Qur’an. Yet, it is true that there are some Sunnahs of the Prophet (peace and blessings be upon him) that are based on a particular culture and tradition, and such type of Sunnah is not considered as legislation for Muslims at all. This type refers to his preference in food, ways of talking, looking and walking, and the colour and type of his dress, etc. This type of Sunnah is known as non-legislative Sunnah and it is not a part of the religion, meaning nobody is obliged to follow it.
Finally, I recommend to the readers to study a wonderful book written by Sheikh Yusuf Al-Qaradawi titled How We Deal with the Sunnah. Surely, you will get a lot of knowledge and clarification about many things related to the Sunnah of the Prophet (peace and blessings be upon him).