The truth is like a lion. You dont have to defend it. Let it loose. It will defend itself.
A large proportion of contemporary philosophies, in fact, consist of saying that man is not capable of truth. But viewed in that way, man would not be capable of ethical values, either. Then he would have no standards. Then he would only have to consider how he arranged things reasonably for himself, and then at any rate the opinion of the majority would be the only criterion that counted. History, however, has sufficiently demonstrated how destructive majorities can be, for instance, in systems such as Nazism and Marxism, all of which also stood against truth in particular.