Would you mind giving me a definition of "Natural Theology"? Doesn't Natural Theology say that we can know everything we need to know about God from the things around us using reason?
No, not at all! Natural Theology is a body of truth that can be grasped by the reason of man aided by the revelation of God given to all men. It is not an exhaustive body of truth, neither is it sufficient for Salvation.
Advocates of Natural Theology define it as follows:
"Simply stated, natural theology refers to knowledge of God acquired through nature. Classically, natural theology does not stand in contradiction to divine revelation nor does it exclude such revelation. In fact, natural theology is dependent upon divine revelation for its content. To be usre, there have been philosophical attempts to achieve a natural theology in isolation from and as a substitute for natural revelation. That we call naturalism. Contrary to naturalism, Christian approaches to natural theology are established upon the foundation of a prior divine revelation. For the Christian, natural theology does not mean that humans, in their natural state, have the intrinsic ability to rise to a knowledge of God by the sheer force of intellect unaided by divine revelation. Such a view is repudiated by Protestants and Roman Catholics alike,..."