You can't say values are irrational -- they just are. If you really like paperclips, no amount of logic can tell you otherwise. What logic can tell you (and other people could), is that your values conflict with each other and you have to balance one against another. Turning whole universe into paperclips is counterproductive if you also value pins. If you literally have no value the other person is basing their arguments on, then they can't convince you to have it.
Luckily we get our values from bunch of heuristics developed through millions of years of biological and social evolution, so we mostly have the same ones, just with different relative weights.
Won't be true if we ever meet (or make) some other sentient critters.