Kalam

[LinuxGal]

If God is the uncaused cause, as neo-Thomists and others assert, then his existence has no reason.  His existence is simply a brute fact. 

And if God's existence has no basis in reason, then there is also no reason to assert he is the solitary uncaused cause.  He may very well be one of many uncaused causes.

Thomists reject Kalam.

On the contrary, it is written (Summa P1 Q3 A3):

The second way is from the nature of the efficient cause. In the world of sense we find there is an order of efficient causes. There is no case known (neither is it, indeed, possible) in which a thing is found to be the efficient cause of itself; for so it would be prior to itself, which is impossible. Now in efficient causes it is not possible to go on to infinity, because in all efficient causes following in order, the first is the cause of the intermediate cause, and the intermediate is the cause of the ultimate cause, whether the intermediate cause be several, or only one. Now to take away the cause is to take away the effect. Therefore, if there be no first cause among efficient causes, there will be no ultimate, nor any intermediate cause. But if in efficient causes it is possible to go on to infinity, there will be no first efficient cause, neither will there be an ultimate effect, nor any intermediate efficient causes; all of which is plainly false. Therefore it is necessary to admit a first efficient cause, to which everyone gives the name of God.