Does Islam forbid critical thinking, as atheists claim?

One must preserve faith, maintain the purity of one's innate disposition (fitra), and keep away from doubts and tribulations. It is not permissible to read books of innovation (bid'ah), superstitions, other religions, or atheism, except for those well-versed in Islamic knowledge who can refute them.

Islam has called for contemplation of the Quran and creation. Allah has condemned the inhabitants of Hell for not utilizing their intellects, as contemplation is an act of worship, as stated in His saying: (Indeed, in the creation of the heavens and the earth and the alternation of night and day are signs for those of understanding) [Quran 3:190]. It is also narrated from the Prophet, peace be upon him, that he said: "Woe to him who recites them and does not contemplate them."