Aquinas wasn’t just under the influence, to some degree, of Catholic crusaders though. He was also blazing a new trail for Catholic theologians by allowing the writings of Aristotle and other non-theologians/philosophers to color his thinking on God. Specifically, Aquinas was among the first to say out loud that he believed a theology (a belief about God) could be arrived at and supported by natural law alone with no backing from scripture or Church tradition.
Natural law, dumbed down so that I can better understand it, is the common sense or practical considerations behind what’s “right” and “wrong.” It’s the “it makes sense” part within us all. People with no understanding of God, who’ve never read the bible, can know not to steal, for instance. Their reasons for respecting the property rights of others are governed by natural law or instinct. That law causes them not to steal on the grounds that they A) don’t want their property taken away in a reprisal or don’t want to be harmed if they get caught stealing and/or B) think that stealing would hurt the common good, the society and therefore possibly hurt them.
So with no influence from the bible, human beings, because we all follow natural law within us to some degree, may still ACT “right” if “right” works best for us and our society. Pragmatism.
Aquinas admitted to forming his additions to Augustine’s Just War doctrine based not upon scripture (Divine law) primarily, but upon this built-in need to be practical and preserve society and self (natural law). He believed this natural law in us all was inherently good because God put it there. So what works, what is arrived at by observing natural, is divine law, is what God calls “right”. This was the beginning of a new era of practical or natural law theology within Christendom which is still alive today.
What beliefs do we hold that have their basis in natural law more than biblical revelation? I have plenty. When, if ever, is that a bad thing? Why?