That's just getting into semantics, which is pointless. What is "truth"? Ultimately, that depends on your point of view. If you base it off of experience (which is how you learn about everything in the first place), then the experience is "truth". If you base it off of something "outside" of yourself, that reference point itself becomes "truth". But of course, that reference point - be it real or not - is still something you imagine is there, and therefore might not be real, and the burden of referencing everything to that "source" of truth still falls on that one thing you are trying to avoid: experience. Sorry for being overly philosophical. For a continuation of this thought, try web searchs for "solipsism" and "world of mind".

Elsewhere in the thread someone gave the example of heliocentrism versus geocentrism. You can form a heliocentric model that makes accurate predictions, you just have to add epicycles to everything. But I would say that heliocentrism is not merely more elegant and more convenient, but also more true. Wouldn't you? For a more extreme example, in the story from http://lesswrong.com/lw/i4/belief_in_belief/ I think we would say that it isn't true that there's a dragon in the garage.

In that case however we have other data than just the model to suggest that geocentrism is false, whereas the topic of this thread is models in physics mathematics that merely differ in complexity, with no apparent difference in "truth".