I can easily claim that the universe never came into existence, and that it has no cause.
Well you can CLAIM the universe came into existence without a cause, but modern Big Bang cosmology points at a determinable beginning point for space-time, matter and energy. That implies you cannot use space-time, matter and energy to explain the origin of space-time, matter and energy. Let’s not bring up Lawrence Krauss because his claim basically amounts to an assertion that the quantum vacuum just exists as a matter of necessity. He provides no basis upon which to make that claim.
The difference is that science cannot pursue a cause beyond space-time, matter and energy because, methodologically speaking, science is restricted to space-time, matter and energy by its very methodology.
So the question moves to logical and metaphysical analysis, which doesn’t rely on pure assertion, but on the principle of sufficient reason. What is sufficient to explain the existence of an intelligible and mathematically complex physical universe when that universe came into existence 14.7 billion years ago? How do we explain it when it logically cannot explain its own existence?
We have no reason to think the quantum vacuum just exists as a brute fact. Nor can a pure brute fact be explanatorily sufficient. That is tantamount to throwing your hands in the air and asserting baldly that it just is without need of explanation. Hardly sufficient as far as an explanation is concerned.
Metaphysically speaking, those who are not materialistic dogmatists begin with the idea that a sufficient explanation does and must exist, otherwise you have to accept that all that exists is purely inexplicable. That, unfortunately, means that drawing the line of inexplicability is entirely a random act based purely on caprice rather than any substantive criteria. Nope, if we are going to assume reality is explicable, we need to pursue that to its logical end, not merely where atheistic materialists conveniently decide based on their own metaphysical presumptions.
What would explanatory sufficiency look like? It exists necessarily and is not contingent. It explains itself along with everything else. It has the capacity to bring all particular and contingent things, including consciousness and formal intelligibility, into existence and maintain them in existence.
Krauss claims a quantum vacuum is the candidate, and further claims he establishes that something can and does come from nothing. Ergo, NOTHING is his candidate for being the necessary and sufficient explanation for everything. Uh huh.
Let’s be real simple here. Which is a better candidate to explain the existence of the complex and superbly precisely ordered universe we happen to live in? Nothing or Aquinas’ Pure Act of Being Itself? You can plead the former – even by pleading your own special kind of nothing – if you think that is reasonable.
You might want to ask yourself, seriously, what cognitive biases you have for preferring a non-explanation as an explanation when an infinitely more Intelligent One is there to be had.