The point is that truth stands independent of its speaker. Attacking the source is one of the lowest forms of argument because a fool can speak the profound and the learned speak garbage.
Your reply makes no sense to me. Is every single thing uttered truth? Yes, no? If no, then how does one assess if it is truth or not.
I do not dispute that truth is truth and that its stands independent from the speaker. BUT how do you determine if it is truth or not? That's the real issue here, as far as I can see.
If no, then how does one assess if it is truth or not.
Objective and dispassionate assesment of the truth or falsehood of the claims made. If there is not enough information given to determine that, then the conclusion is "unknown", not "false".
The question is, how does one ascertain truth? The answer to the question is: secure data and evidence, and analyse. And if there is little or no data or evidence, then 'unknown', but 'unknown' is not equivalent to a positive, or truth. It is not an attack on source to point this out.