In Islam, there are well-defined requirements with regards to the amount of knowledge a lay-person is required to attain. On the matter of beliefs, theology, cosmology, etc. the criterion is something like, "the subject must be studied sufficiently to be able to remove the doubts that are a person is capable of understanding". So for example, an illiterate Muslim bedouin is only required to understand the analogy between footsteps in the sand that indicate on the presence of a person having walked and the wonderous creation indicating on the presence of a creator. On the other hand, a Muslim that has a Ph.D. in philosophy has the responsibility to study deeply the cosmological and other rational arguments that justify every level of belief.
The bedouin can't be faulted for not studying to the level of the Ph.D. and the Ph.D. can't be faulted for not accepting without question the reasoning that was sufficient for the bedouin.