St. Thomas Aquinas writes in his book “On Being and Essence” that a small error can lead to significant errors later on. This work of his is likely one of the most important when addressing his proof of God’s existence. This particular proof of God’s existence does not explicitly find itself in His traditional five-ways, because it is one of the more complicated proofs of God’s existence. St. Thomas wrote the Summa Theologica, at his time, for beginners. The education environment of his day would have meant that people were familiar with his language, with logic, and with the fundamental basis to understand what he wrote. That simply isn’t the case today, as logic is generally taught at the end of High School, which actually inverts his pedagogical method.
Take William Lane Craig as an example; he is a believer, and a brother no less in the faith to us all. He is an advocate for reason, and has certainly convinced many people of God’s existence. Nonetheless, because of his metaphysical view, he ultimately believes that Christ has one will, and consequently that each person of the Trinity has one will. That is heresy. He would seem to be consistent in his own views, but that little metaphysical error nonetheless leads to a rejection of what is manifest in Scripture about the human and divine dynamic of Christ’s two wills.
Where people take on the task as theologians and philosophers, we have to grasp the gravity of such work. It is a science, and requires severe discipline, otherwise for those who adhere to such a teaching, or seek development, are going to be led astray and begin to worship a God that is false.
It would be wise to assert that there is a significant relationship between the speculative virtues and the relationship with have with God. Whoever God is to us, is that whom we internalize. All sorts of heresies lead to poisoned spiritual dispositions that end up alienating us from a relationship with God that liberates the soul to Love Him for who He really is. To reject or be averse to heresy is an act of loving God, because we are not indifferent to who He is. Thus, if we love God, we will seek to avoid even the littlest of errors. All of us will undoubtably make such errors, but we nonetheless should try to avoid them.
Posterior to St. Thomas Aquinas’ philosophy, fideism and rationalism developed as an end result of rejecting the notion that Christ was “ipsum esse.” From within the Church various forms of nominalism reemerged, and the relationship between faith and reason took a hit. Christian began to suggest that treating theology as a type of science was to place God into a box, reducing Him to some logical category. Rather than seeing logic as a revelation into the very nature of God, theology was perceived to have become some limiting act against God.
Contradictions would be espoused by some, as though God could contradict himself. God could create “prime matter” without actuality. Such a simple suggested unravels the proof of God’s existence, the nature of God’s divine simplicity, and even seems to posit, indirectly that God can contradict Himself. Nature was no longer revelatory, rather it stood separated from God, distinct, as a separate being from God as another type of being. No longer was the very existence of nature a matter of us brushing our mind up against God, and saying things of Him through the analogy of creation.
From this vantage point, eventually God become deistic. He was removed from creation entirely, like a watchmaker. No longer could his total-difference as “ipsum esse” be reconciled with creation, but now he existed in some competitive state. Unlike the bush that was on fire before Moses, God was incompatible with creation, as were the sciences. It was heralded as a liberating act for God to say He could contradict himself. It was perceived to mean that God was not confined by reason. But in doing this, we lost the notion that God was Divine-Reason, and that in some ways He was the very essence of non-contradiction: He is Truth.
I good book recommendation on this matter, that I would recommend for those aspirating philosophers and theologians on this matter is “The Unintended Reformation: How a religious revolution Secularized Society.” Not only does the book note the direct affect of the reformers on the change in the academic and social sphere of the west, but it also addresses the precursing theologians and philosophers from within the Church. In our day, I do believe there needs to be a more disciplined approach to studying the faith, and less of a gnostic (experience-based type of knowledge). The experience and encounter is emphasized today for good reason. However, it needs, as always, to be submitted to the Church for proper articulation and internalization. Consider reading this book to assess how the world got to where it is today, as influenced by thinkers.
Dr. Gregory’s book you mentioned has earned for him the “Gregory thesis,” that the Achilles heel of modernity is basically Luther’s view of conscience which leads to subjectivity. Kant’s distinction between noumena and phenomena cements this in modern philosophy. The result of this loss of objective facts, truth and reason is chaos in all facets of western civilization.