Here is a brief account of two parallel realities, one is from the biblical perspective and the other from the philosophical:
— “For God knows that in the day you eat from it your eyes will be opened, and you will be like God, knowing good and evil.” ~Satan
— “Cogito ergo sum,” or “I think therefore I am.” ~Rene Descartes
We are dealing with anthropology here, or what it is that defines man. Rationalism has been articulated by many throughout the history of the church, many being theologians. The maxim I mention is “Cartesian rationalism,” we also have other versions (with similar consequences in general) like Thomas Aquinas’ version of rationalism which has been called the Intellectualist strain; what is common to all rationalism[s] is that they hold that “man’s rationale” or “intellect” or “mind” is the defining feature of man. As we can see from Rene above, the consequence of such anthropology is that man becomes the standard by which all reality is adjudicated; even God.
Do you see how “rationalism” = the original lie offered to both Eve and Adam?