Liars are people who claim untrue things
knowing that they're untrue. You are not a liar for claiming an untruth that you believe is true. I disagree with many, many people on these forums, but, except for the periodic POE troll, I don't think any of them are liars.
As Jay pointed out, and as I kinda realized not long after posting, my programming example is very, very poor. Since that involves a real-life skill and trade, you absolutely should double-check claims made about it if it's important enough for you to know. (Which WILL give you headaches, because programmers can sometimes be rather... zealous about the perfectness of their particular favorite techniques, and the stupidness of all other techniques).
Now, obviously if we ask for "evidence" for everything we hear from other people, including mundane stuff like "it's my birthday today!" (which, I
swear by Loki's fabulous hair is
SHEER coincidence
, it actually is), then casual interactions would be cumbersome and unwieldy. But not all human interaction is the same.
In the context of a debate, any newly presented arguments need to be supported, or there's no reason to believe them. When I say it's my birthday, that's not an argument. When I say that boolean variables MUST be set to false at all times in programming unless there's good reason not to, that is an argument which can be discarded without proper support.
This is THE reason why in the US justice system (ideally, anyway), a convict is innocent: i.e., the claim that they broke a law is assumed false; until proven guilty: the claim is proven true.
BTW, I do think before I post. I think on my posts for several minutes before making them; it's not unheard of for me to think on a single post for a whole hour before posting it. Often, it also involves something I'd been thinking about in my own time. The quality of an argument rarely as anything to do with the "quantity" of thought that was put into it. After all, it's also not unheard of for some of these long-thought-out posts to be dismissed because I was thinking in the completely wrong direction. That's why I'm here: to help guide my thinking.