Al-Ma'mun was very interested in working on various sciences translated into Arabic.
Thus he arranged debates between the Imam and Muslim scholars and the leaders of religion sects who came in his presence.

One of the discussions was on Divine Unity with Sulaiman al-Mervi; a scholar from Khorasan, another discussion with Ali ibn Muhammad ibn al-Jahm was devoted to the sinlessness of the Prophets, which led to another debate on the same subject which Ma'mun took a great part in it himself.
Many of these debates are recorded in the collections of Shia hadiths, like Oyoun Akhbar Al-Ridha.
The following is an example of these debates which took place between the Imam and an unbeliever(Zindīq).

(The Imam) said to him (Zindīq), "Dost thou see that if the correct view is your view then are we not equal?
All that we have prayed, fasted, given of the alms and declared of our convictions will not harm us.
If the correct view is our view then have not you perished and we gained salvation?"

the Man said. "
Then let me know, how is He and where is He?"
Abu-l-Hasan(the Imam)answered, "surely the opinion thou hast adopted is mistaken.
He determined the 'where', and He was, when there was no 'where'; and He fashioned the 'how', and He was, when there was no 'how'.
So He is not known through 'howness' or 'whereness'" The man said, "So then surely He is nothing if He cannot be perceived by any of the senses."
Abu-l-Hasan said, "when our senses fail to perceive Him, we know for certain that He is our Lord …" The man said, "Then tell me, when was He?"
Abu-l-Hasan said, "Tell when He was not, and then I will tell you when He was..." The man said, "Then why has He veiled Himself (from men)?"
Abu-l-Hasan replied, "Surely the veil is upon creatures because of the abundance of their sins.
As for Him, no secret is hidden from Him during the day or the night…"
This is a long debate, entitled, The Veil, full text of which could be found in the A Shiite Anthology translated by William Chittick.
According to some accounts, Ma'mun's main objective of holding the meetings was a hope to render the Imam incapable of answering questions in order to undermine his popularity.
It is related from al-Nawfali who quoted the Imam as saying
Would you (al-Nawfali) like to know when al-Ma'mūn will feel remorseful? ...
When he hears me argue with the people of the Torah quoting their own Torah, with the people of the Gospel quoting their own Gospel, with the people of the Psalms quoting their own Psalms, with the Zoroastrians arguing in their Persian language, with the Romans in their own Latin... then al-Ma'mūn will realize that he will not achieve what he aspires...
Al-Ma'mun was very interested in working on various sciences translated into Arabic. Thus he arranged debates between the Imam and Muslim scholars and the leaders of religion sects who came in his presence.
One of the discussions was on Divine Unity with Sulaiman al-Mervi; a scholar from Khorasan, another discussion with Ali ibn Muhammad ibn al-Jahm was devoted to the sinlessness of the Prophets, which led to another debate on the same subject which Ma'mun took a great part in it himself. Many of these debates are recorded in the collections of Shia hadiths, like Oyoun Akhbar Al-Ridha. The following is an example of these debates which took place between the Imam and an unbeliever(Zindīq).
(The Imam) said to him (Zindīq), "Dost thou see that if the correct view is your view then are we not equal? All that we have prayed, fasted, given of the alms and declared of our convictions will not harm us. If the correct view is our view then have not you perished and we gained salvation?"
the Man said. "Then let me know, how is He and where is He?" Abu-l-Hasan(the Imam)answered, "surely the opinion thou hast adopted is mistaken. He determined the 'where', and He was, when there was no 'where'; and He fashioned the 'how', and He was, when there was no 'how'. So He is not known through 'howness' or 'whereness'" The man said, "So then surely He is nothing if He cannot be perceived by any of the senses." Abu-l-Hasan said, "when our senses fail to perceive Him, we know for certain that He is our Lord …" The man said, "Then tell me, when was He?" Abu-l-Hasan said, "Tell when He was not, and then I will tell you when He was..." The man said, "Then why has He veiled Himself (from men)?" Abu-l-Hasan replied, "Surely the veil is upon creatures because of the abundance of their sins. As for Him, no secret is hidden from Him during the day or the night…"
This is a long debate, entitled, The Veil, full text of which could be found in the A Shiite Anthology translated by William Chittick. According to some accounts, Ma'mun's main objective of holding the meetings was a hope to render the Imam incapable of answering questions in order to undermine his popularity. It is related from al-Nawfali who quoted the Imam as saying
Would you (al-Nawfali) like to know when al-Ma'mūn will feel remorseful? ...When he hears me argue with the people of the Torah quoting their own Torah, with the people of the Gospel quoting their own Gospel, with the people of the Psalms quoting their own Psalms, with the Zoroastrians arguing in their Persian language, with the Romans in their own Latin... then al-Ma'mūn will realize that he will not achieve what he aspires...
Ali al-Ridha