Atheism :: circularity

The atheistic worldview holds that we are able to (a) use our senses to gather data about the universe, and (b) use our human reason to discover truth based on the input of our senses. Is there a problem with this system?

(a) We have no way of verifying the input of our senses except by the use of our senses. This is circular.

(b) We have no way to verify that our reasoning produces valid results except to examine the results using human reasoning. This is also circular.

Appealing to the fact that our experience agrees with that of others doesn't solve these problems because we have to use our senses and reasoning to communicate with each other and to process the information we communicate.

Do theists have the same problem?

Christian theists --- moi, for example --- hold that outside of the closed system of the material universe there is another entity, whom we refer to as God, whose nature provides our senses and reasoning with a foundation from outside of the closed system. Human reasoning can be grounded on something external to the material universe and can therefore be able to produce valid results.