11. A number of our people have narrated from Sahl ibn Ziyad from Isma’il ibn Mehran from Muhammad ibn Mansur al-Khuza’i from Ali ibn Suwayd who has said the following:

“Once I asked abu al-Hassan Musa about the feeble-minded people and he wrote to me, ‘A feeble-minded is one to whom evidence and proof is not (or cannot be) presented and he does not know the differences among people. If he knows the differences among people he is not an enfeeble person.’”