The Principle of Contingent Causation: The Impossibility of Infinite Regress.

[Thumpalumpacus]

No, it's a key part of Thomas's argument that anything which is non-contingent has not come to be. And this includes, of course, a First Cause. He thinks that the First Cause is the only non-contingent thing.

That sounds pretty immortal to me, yet you deny above that this is part of Aquinas's argument.

Do you think that Thomas argues that God came to be? The whole point is that he never came to be, he is the only non-contingent, uncreated thing.

So if he wasn't created, then he is indeed immortal. You can't eat your cake and have it too.

"Contingent' means that they depend for their existence on something else. "Non-contingent" means that they don't. The non-contingent First Cause (which Thomas says is the only non-contingent thing) hasn't come to be. 

Meaning it has always been there. Meaning it's immortal.

Currently it appears that some quantum events occur without an efficient cause. As I explained earlier in the thread, the causes that Aristotle and Thomas talk about are not only efficient causes. 

To repeat: for them, the causes of X are all the things that must be the case in order for X to be the case. All quantum events depend for their occurrence on other things being the case -- for example, the existence of space/time. Therefore, in the sense of αἰτία, which is what Thomas is talking about, all quantum events are caused.

And you're certain that the existence of the universe itself is not a quantum event?

Thomas argues that one non-contingent thing does exist, but hasn't come to be. It couldn't come to be, because there is nothing essentially prior which could cause it to come to be. 

Which is the special pleading I've already pointed out.

"Come to be" is not the same as "exists." It means "begins to exist." Thomas thinks that God exists, but never came to be.

Which is, of course, an undemonstrated assumption.

You added the idea that it has to last forever, which is of course a Christian belief, but isn't covered in the Argument from Contingency. 

Incorrect, as I showed in my post immediately preceding this.

As to why the non-contingent thing is necessary for contingent things to exist, that's what the thread is about, and it's been covered several times already.

You cannot simply proclaim the necessity. You must demonstrate it. Thus far you haven't done so. Do you have anything new to add that would make Aquinas's arguments valid? I'm tiring of nailing you Jell-O to the wall.