This is a once taken, always applicable decision.
It can, indeed, be shown that no generally applicable decision procedure for LPC is possible i.e., that LPC is not a decidable system.
As radical as the respective #3s are, Brouwer and Wittgenstein agree that an undecided φ is a mathematical proposition (for Wittgenstein, of a particular mathematical calculus) if we know of an applicable decision procedure.
If a genuine mathematical proposition is undecided, the Law of the Excluded Middle holds in the sense that we know that we will prove or refute the proposition by applying an applicable decision procedure (PG 379, 387).
On this interpretation, the later Wittgenstein precludes undecidable mathematical propositions, but he allows that some undecided expressions are propositions of a calculus because they are decidable in principle (i.e., in the absence of a known, applicable decision procedure).
Thus, the later Wittgenstein agrees with the intermediate Wittgenstein that the only sense in which an undecided mathematical proposition (RFM VII, §40, 1944) can be decidable is in the sense that we know how to decide it by means of an applicable decision procedure.
When, therefore, Wittgenstein says (PG 368) that if "[the Law of the Excluded Middle] is supposed not to hold, we have altered the concept of proposition," he means that an expression is only a meaningful mathematical proposition if we know of an applicable decision procedure for deciding it (PG 400).
(Against Weyl and Brouwer)." The point here is not that we need truth and falsity in mathematics we don't but rather that every mathematical proposition (including ones for which an applicable decision procedure is known) is known to be part of a mathematical calculus.
If, as Brouwer says, we are uncertain whether all or some "mathematical problems" are solvable, then we know that we do not have in hand an applicable decision procedure, which means that the alleged mathematical propositions are not decidable, here and now.
On Wittgenstein's intermediate view, PIC like FLT, GC, and the Fundamental Theorem of Algebra is not a mathematical proposition because we do not have in hand an applicable decision procedure by which we can decide it in a particular calculus.
