Efficient Cause Who and what is God? Why do some people adamantly conclude that a God exists? St. Aquinas goes from believing that there must be an efficient first cause to the conclusion that God is that cause. Why must Aquinas make such an extraordinary jump from there being a cause, to assuming that this cause must be God? In a scientific point of view, wouldn’t it be just as plausible to make matter the first cause? After all, according to the Law of Conservation of Matter, matter cannot be created nor destroyed. Matter is the sub ....