By the scientific evidence...

By the scientific evidence, we can prove that al-Mahdi is not just a myth or a supposition but a reality which has been confirmed by historical experience The Islamic evidence appears in the hundreds of narratives related from Allah's Messenger (peace and blessing of Allah be upon him and his progeny) and the Imams of Ahlul Bayt (peace be upon them), which prove that al- Mahdi will be appointed as Imam, that he is from the descendants of the Prophet and Fatimah and the ninth descendants from al-Husayn, that the caliphs (Prophet's successors) are twelve.

All of these narratives limited that universal idea by personifying it in al-Mahdi, the Twelfth Imam of Ahlul Bayt . Moreover they reached a great number and diffusion, although the Imams took a great precaution and care, fearing their exposure on a general level, in order to protect the righteous descendants against assassination or an unpredicted assault on his life.

However, the numerical abundance of these narratives is not the only reason for their validity, for in addition to this, there are certain virtues and coherences to be taken into account for proving their validity.

The Prophet's narratives ( ahadith ) about the fact that the Imams, caliphs, or amirs - depending on the style of the narrative in its different ways are twelve Some writers counted up to more than two hundred and seventy narratives taken from the most well-known books of Sunni and Shi'ah traditions such as al-Bukhari, al-Muslim, at-Tirmidhi, Abu Dawud and the collection of Ahmad ibn Hanbal and the Rectification of the Judge on the Two Sahihs (al- Hakim, Mustadrak 'ala s-sahihayn ).

We should bear in mind here that al-Bukhari who had compiled these narratives, was a contemporary to both al-Imam al-Hadi and al-Imam al-'Askari which means quite a lot, since it proves that the narratives were recorded from the Prophet (peace and blessing of Allah be upon him and his progeny) before that the realization of their contents and the idea of the Twelfth Imam had materialized.

This means, therefore, that there is no room left for doubt, that the recording of the narratives was not influenced by the fact of the Twelfth Imam, or that it might have been a reflection of it, because the false narratives ( ahadith ) that are related from the Prophet ( peace and blessing of Allah be upon him and his progeny) are either a reflection or a justification for a fact occurring later in time.