Learn Turkish: Kimse bu saçma hurafeye inanmış olamaz. - Nobody can have believed this absurd superstition.

This structure combines the past/perfect suffix -mış with olamaz (the negative potential aorist of olmak, meaning "cannot be"). Literally, it means "cannot be in the state of having believed." This is the standard Turkish way to express a strong deduction that something did not happen in the past.

Why is kimse translated as "nobody" here? Doesn't it just mean "someone" or "anyone"?

Kimse translates to "nobody" when the verb of the sentence is negative. Because our auxiliary verb olamaz is negative, kimse automatically takes on a negative meaning. Turkish doesn't use a separate negative word for "nobody" in these cases.

Why is the word hurafe (superstition) written as hurafeye in this sentence?

The verb inanmak (to believe) always requires its object to take the dative case (-(y)e or -(y)a). You essentially believe "to" something in Turkish. So, hurafe takes the buffer y and the dative e, becoming hurafeye.

What is the difference between inanmış olamaz and inanmamış olabilir?