The subject of zombies is one of the most discussed and controversial topics of philosophy of mind. In this paper I will first examine the main argument of zombies, providing a summary of the current discussion. Then I will introduce a thought experiment, an epistemic window on a metaphysical scenario. By the thought experiment I will argue that zombies are logically impossible. Further I will discuss another recent epistemic window. Finally I will provide some other logical consideration to prove that intentionality is not reducible to the cognitive functional aspects of the mind and that, moreover, the subjective recognition of semantic contents is necessary in order to consider as sensical the verbal behavior of a zombie.