Ok, I think I understand. This is taking us further than the confines of Truth. I should qualify this. However it is my impression that the ablity is assert something is distinct from warented assertablity. To be able to assert something one need only have cognitve command of whatever language the assertion is made in.
Children are very good at amking assertions which are unwarrented to a higher degree than adults.
They still assert and that is because they understand the language. To have warrent one needs cognitive command of both the language and what ever subject on which the assertion is made, I think. So, when Maj. Gen. Gertz asserts there were 700 sorties flown over Kosovo yesterday I assume he has warrent to assert this because he is in a position to know. One can also be warrented if one asserts something that is well founded in our cultural history.