What constitutes a theory? Is it nothing more than a collection of statements? yes, then what? a collection of ideas? does an idea become more than a statement in certain discourses and not in others?
We have established that one theory can not be more true than another, that is a basic premise of something that is constituted by what it is not. Also it is commonly accepted that truth is theory specific. That is what is true under one theory may not be true under another.
This leads to a definition of a theory as a set of statements that establish truths, but what then makes one theory more true than another. To say that 2+2 = 5, I know it to be true! but does that make it more true than 2+2 = 4, which so many others know to be true. These single statements are not in and of themselves meaningful independent of their theories. But take then the two competing theories. 1. Standard Math. 2. Everything George Orwell wrote is correct. By the first 2+2=5 is nonsense, by the second it is truth. So what is the standard of truth of theories? Logic? Rationalism? ....of course not....broad social acceptance? This can not be truth as it would render Marxism a lie!
More importantly is truth meaningful in a postmodern world? What matters that I know 5? if discourse around it finds that it is a lie? what matters that we know Marx, when there is no discourse around Marxism?
Perhaps the Keynesians have it right! Perhaps all is fundamentally unknowable and we should hedge our bets! blah! and perhaps disco was real music and John Lennon got it wrong but I don't think so. Ah to not fall back into a meaningless phrase for a conclusion.....ah worlds with truth may be empty but they result in less sleepless nights.