for one thing, the causal principle is not compositional in nature - it is a
principle.
for another, so what if compositional arguments are not universally valid? nothing about the first cause argument depends on the universal validity of compositional arguments - if it depends on compisitionality at all, it depends only on the the compositionality of a
singular case.
you would have to demonstrate not the (uninteresting) point that some compositional arguments are fallacious, but that the
specific compositional argument (allegedly) used in the first cause argument is fallacious.
in the same way, the fact that some compositional reasoning is invalid in no way impugns the validity of:
- every brick in the wall is stone;
- therefore the wall is stone.
neither does it impugn the validity of :
- every thing in the universe is caused;
- therefore the universe is caused.
if you want to make
that case, you’re going to have to make a
further argument that the universe is something more than its constituents, perhaps by making an appeal to mereology, or something. but watch out for the (unnecessary) multiplication of entities and ockham’s razor…