Creation meant that we also found ourselves in the presence of others and of things, both of whom also call to us, demanding our response by posing problems and questions, whether explicitly or not. If we take those calls seriously, being sufficiently faithful to the things and persons that make demands on us that we make adequate responses to their calls, we act rationally.
Because we exist, we account for ourselves before God, in relation to others, and in the world. We cannot avoid giving those accounts; we cannot avoid reason. But reason is not contradictory to faith, for reason begins in an act of faith (trust and fidelity). Reason requires faithful response to those beings who surround and precede us, whose very existence calls to us, making demands on us that interrupt our being: first God, then persons, then things.
And, of course, not only does reason require faith, faith requires reason. They are not the same, but either without the other is lame or blind or both. Faith makes it possible for us to talk, to reason, with God, with each other, and with the world. Together faith and reason make it possible for us to live responsibly, responsively.