Well, no. If the universe came into existence 13.7 billion years ago, then its continued existence is dependent upon whatever brought it into existence. This was Aquinas’ point when he distinguished between **accidental **and per se causality.
A series of accidental causes could, he argued, go on through infinite time, but would still depend upon per se causality to sustain the series itself since the “accidental” nature of the causal relationships within the series means it must have dependencies outside of the causal sequence that must be referenced to explain why the interconnectedness exists. The sequence cannot exist a se, but can only exist by virtue of whatever it was that bestowed its nature (i.e., the set of causal dependencies within the series) and sustains it. An accidental series requires an explanation outside of the series.
Aquinas’ example was the generation of living things. The fact that progeny can "self-regulate” and survive independently of their parents does not mean they can survive a se (exist by their very nature.) It only means they can survive independently of the agents (parents) that brought them into being. The entire process of reproduction, however, is itself dependent upon the existence of per se causality which keeps each living thing in being. Living things (accidental causes) might exist independently of who or what brought them into existence, but, ultimately, accidental effects in any series depend upon per se causes.
A per se series of causes is the only possible explanatorily sufficient series because it properly and fully identifies (and explains) what bestows existence itself on any effect. Suppressing any one (or first) cause in a per se series directly suppresses the effect, effectively ending its existence or obtaining in reality. It is in understanding per se causality that we begin to understand that existing things that come into being can only be ultimately explained by per se causality, i.e., causality which originates from that which does exist by virtue of what it is. Only if something exists a se (having the explanation of why it exists integral to the nature of what it is) can we ever arrive at a sufficient explanation for why things exist at all. Otherwise, we could ultimately explain nothing whatsoever.
The universe does not explain itself, nor does it exist a se, since it came into being 13.7 billion years ago. It could only explain itself if it did exist a se (simply by virtue of what it is) but if it came to be then it need not exist and therefore why it came to be must find its explanation in something outside of it, since it does not and cannot explain itself or why it came to be. Things that come to be CANNOT explain why they did come to be.
Things don’t bootstrap themselves into being – not even universes – otherwise we would have reason to accept that anything could just pop into being without reference to a sufficient cause to explain why it did.
