[quote=Suat]Yes, but I fail to see why the universe needs a first cause but God does not. Saying that God does not need a first cause because you define him as uncaused does not count
You’ve missed the entirety of Aquinas’ argumentation if you cannot understand the necessity of an uncaused cause. Reconsider the boxcar analogy referenced in the original article:
Imagine a series of boxcars, in which each boxcar moves as it is pushed by the one behind it:
O >>> O >>> O >>> O >>> O >>> O >>> O >>>
In this illustration, the motion of each boxcar is dependent upon the boxcar behind it. (This series of boxcars is “the universe” taken in its entirety; all events constituting the universe are caused by previous events.)
Now, if the movement of every boxcar is dependent upon the boxcar behind it, then how did the entire series begin to move? The entire series of moving cars must ultimately depend upon a “prime mover,” identified as “A” below:
A >>> O >>> O >>> O >>> O >>> O >>> O >>>
As the occupant of the first position in this series, “A” is an uncaused cause; all cars depend upon it for motion, but it does not depend upon something else. In deism and theism, this prime mover is “God.”
Now, you assert that “God” would also have to have a cause, finding the designation “uncaused cause” a clever cop-out. Alright then; let’s return to our diagram and deny that an “uncaused cause” can exist, so that “A” is also caused, just like all the other boxcars:
B >>>** A** >>> O >>> O >>> O >>> O >>>
Now, “A” has a cause as well (“B”). Well, what caused “B”? Something must have, since we excluded the possibility of “uncaused causes.” Let’s assume the cause of B is C. What’s the cause of C? D. And the cause of D? E… F… G… H… I… J… K… and on to infinity. Ultimately, our boxcar series would have an infinite regression of causes, correct?
Now, here is the key question: is an infinite regression of causes sufficient to explain the motion of the entire series? The answer is no. An infinite regression of causes is no answer in all. Rather than provide us an answer to our question, it postpones it indefinitely. Thus, it is an insufficient answer.
Likewise, the claim that no answer is needed to explain the motion of the entire series is also insufficient (and fallacious), since we stated at the very beginning that the movement of every boxcar in the series was dependent upon the movement of the one before it. We cannot divorce the concept of “movement” from the relations between the boxcars. Therefore, we cannot state that the universe itself is sufficient to explain the cause-effect relations constituting the universe (that would be the true “cop-out” answer).
Ultimately, the ONLY sufficient answer is that an “uncaused cause,” positioned at the beginning of the series, effects the motion the entire sequence of “caused causes.” The observation that we live in a universe of dependent (caused) events compellingly argues for the existence of an independent (uncaused), prime mover.
This is “why the universe needs a first cause but God does not.”