My problem with philosophy is that it appears to have few standards for what constitutes a correct answer to a question, or for what constitutes a well-formulated question.
So, take, for example, theories of truth. Last I've heard, "correspondence theories" (a sentence is "true" when it corresponds to certain states of the external world, called "facts") are actually considered very problematic, precisely because they leave little way of characterizing "truth" in such "a priori" fields of knowledge as mathematics and philosophy. Instead, what's currently popular are minimal or deflationary theories of truth (a sentence "X is true" means just X). Problem is, this theory appears to say nothing at all about truth; as Wittgenstein lambasted, it only says something about words.
So yes, if I say that "X is true" and "X" are equivalent sentences, I've said something about sentences, but I haven't said a damned thing about the contents of the statement X itself!
Mathematical statements, at least analytically speaking, are mostly actually hypotheticals conditioned on an enumerable set of axioms and a formal logic; with those, we can use a coherence theory of truth, in which a statement is true iff it does not contain an internal contradiction. But then you've thrown out most forms of mathematical Platonism, which is, and I do loathe this, the most popular philosophical interpretation of mathematics.
(I loathe it because mathematical Platonism is so often used as a starting example to support a fully general philosophical Platonism, in which statements about theories of truth or morality or knowledge are made in reference to Philosophical Abstract Objects. These have no extension inside space-time and also are not any kind of mental or computational manipulations or constructions (http://plato.stanford.edu/entries/platonism/), and are taken as necessarily constituting the only correct answers to philosophical questions, thus neatly yielding a kind of unique epistemological authority for the philosophical process of arguing and analyzing sentences, which is utterly absurd from a naturalistic perspective.)