Validation

Is what someone says invalidated by either who they are/were or what they erroneously said about another area?

I wouldn't think so as the logic or truth of an argument on it's own should be able to be supported by the very logic or truth of the actual subject, which is the argument, not the person. Yet, when discussing facts, ideas, "truths" with someone of a different mindset they try and attack the person rather than the idea. Either because the issue is too hard to tackle or just that it is their habit to do so. It's a fairly petty tactic but it does have its draw too. One could argue that the idea itself only could have taken form in the mind along with the other wrong assumptions they made or mistakes they committed. The problem is getting drawn into that sort of argumentation in the first place. If I hold what some historical figure said to be of value, and someone attacks that persons life or ideas in another area I have to make a choice. I could start to irrationally defend the person to preserve my initial point or laugh at that sort of logic. Ignore what the person said and just say this: If I said that I spoke a certain idea, or that a friend had whom the "attacker" did not know, then they would only be able to discuss with me what was brought up. They would not be able to bring up other, round-about arguments that deflect attention from what was being discussed. In other words I am discussing an "ad-hominim" argument.

I could have simply written a post that read: "I hate when someone uses an ad-hominim argument!" But that wouldn't have been enough for some reason. ;)