Suppose the laws of physics was the first thing in the universe. Their existence can't be explained, but QFT would be a second or greater thing able to be explained by the existence of the laws of physics.
You're assuming the "laws of physics" are some set of physical-like things that need to come into existence before QFT can operate. But the laws of physics are our mathematical models of the way we see the universe operate. At present we have no evident explanations of what preceded the universe so it is impossible to tell what processes there were or were not. But to explain
this universe, as per your syllogism, all it would take is the operations of QFT or some QFT-like process.
It may be that the "first thing" was caused by a quantum fluctuation operating from nothing.
3. This first thing was caused by a quantum fluctuation operating from nothing.
a. Therefore it can be explained.
4. Therefore the universe can be explained.
We just don't presently know for sure if the explanation is correct.
Edited by AZPaul3, : finish
Edited by AZPaul3, : No reason given.