ectypal.net

There has been, since roughly the eighteenth century, an underlying assumption of reason's capability to know God on its own ("unaided reason"), an assumption that is at odds with Reformed orthodoxy.

It is the categories of Reformed orthodoxy prior to the Enlightenment, therefore, that give us better clarity in our discussion of faith and reason. Given those pre-Enlightenment categories, both the cognitio insita and the cognitio acquisita were elements of natural theology, but-and this is all-important-natural theology itself was defined in terms of its relationship to faith.

In other words, a distinction developed after (and based on) Calvin with respect to natural theology between two kinds of natural theology-a distinction that was obscured and virtually erased after the Enlightenment. The distinction was between a theologia very (true theology) and a theologia falsa (false theology). The former, theologia vera, was also referred to as theologia naturalis regenetorum (natural theology on the basis of regeneration). That is, natural theology could only be true theology if developed by and in the context of the regenerate (faith), since only then would it be based on God's revelation in Scripture.

Unbelievers, on the other hand, must inevitably develop a theologia falsa since they will always and by nature twist and pervert the knowledge of God given both within them and without them. This is the case because reason does not have the ability in and of itself to ascertain truth with respect to God and his existence. It must be governed by faith.