 A dialetheist can reply that, again, not all contradictions are equal. Each sentence, including each contradiction, is evaluated on its merits. While a case can be made for the claim that the Liar sentence is both true and false, but this in no way shows that a case can also be made for Brisbane being and not being in Australia. (Of course, if one subscribes to the claim that entailment is explosive, a case for one contradiction is a case for all; but if entailment is paraconsistent, this argument is of no use.) 