Abū al-ʿAlāʾ al-Maʿarrī was an Arab philosopher, poet, and writer. [en.wikipedia.org]
Despite holding a controversially irreligious worldview, he is regarded as one of the greatest classical Arabic poets.
Born in the city of al-Ma'arra (present-day Ma'arrat al-Nu'man, Syria) he is described as a "pessimistic freethinker", al-Ma'arri was a controversial rationalist of his time, citing reason as the chief source of truth and divine revelation. He attacked religious dogmas and practices, was equally critical and sarcastic about Judaism, Christianity, Islam and Zoroastrianism, and became a deist. He advocated social justice and lived a secluded, ascetic lifestyle.
He was a vegan, known in his time as moral vegetarianism, entreating: "do not desire as food the flesh of slaughtered animals / Or the white milk of mothers who intended its pure draught / for their young".
If only that were true. It is confounding that many intelligent people remain fervent believers. The segregation of religious belief from knowledge and understanding seems paradoxical. Shame on them for not applying critical thinking to their childish delusions.
What you call intelligent is really a matter of judgement. If you cannot distinguish between reason and unexplained belief or belief due to fear, he is not intelligent. Now education is a different matter. Educated does not mean the ability to decipher fact from fiction. I found that out in the immediate family.
The religious throw a lot of big words around to impress on us that their side has been validated by the highly educated, scientists, philosophers and thinkers. To me, anyone who believes in a religion - primitive or modern is not intelligent.