If Lonergan is a "relativist" and critical realism isn't metaphysical realism, then its unclear what bothering with his cumbersome commitment to metaphysics gets us that we can't just as easily get by ignoring it all together. If, at the end of the day, our response to any claim is "prove it," and obtaining proof is a human endeavor, then its unclear how "critical realism" is different than good 'ol fashioned pragmatism. If you admit that "knowledge of reality" is always provisional, then its still unclear why one would insist "reality" matters in the first place.