Ad Hominem/Quotes

Let's also stipulate (this happens to be true) that Isaac Newton had bouts of "crazy" behavior later in life -- probably due to his incautious handling of mercury during his experiments.
If we thus conclude Isaac Newton was a "kook," does this make it safe to step off the balcony of a high-rise building, confident that Newton's characterization of the laws of gravity don't accurately predict our subsequent tumble to our deaths?
No. The theory of gravity stands or falls based on how it explains observable phenomena in the real world, not on whether we approve of Isaac Newton's style of dress, whether he used the correct fork at dinner, or whether he occasionally crawled around on all fours chattering like a badger.

—Vin Suprynowicz, Tortoise breeding endangers Fish & Wildlife jobs

Jerry: You do know I'm right!
Tom: Why?
Jerry: You've resorted to abuse.
Tom: ...Shut up!

—The Good Life

"When you have no basis for an argument, abuse the plaintiff."

—Cicero

"The thing I love about this is, on the internet, people make a big deal out of the distinction between calling someone names as a way of refuting their arguments, and calling someone names just as a kind of a hobby."

—Lore Sjoberg

"Sure, he's an asshole. Sure he's dead. Sure, I'm just imagining that he's talking. That doesn't stop the bastard from being absolutely right."

—Dwight, Sin City: The Big Fat Kill

"When folks start throwing around terms like "trolls" and "harassers" they better back that shit up with some examples.
What they're almost always talking about are people who don't agree with them."

—Forbin on a 2016 GamesIndustry.biz article criticizing Steam's community, /v/GamerGate thread (Voat)

When people have actual reasons for disagreeing with you, they offer those reasons without hesitation. Strangers on social media will cheerfully check your facts, your logic, and your assumptions. But when you start seeing ad hominem attacks that offer no reasons at all, that might be a sign that people in the mass hysteria bubble don’t understand what is wrong with your point of view except that it sounds more sensible than their own.

—How To Know You’re In a Mass Hysteria Bubble, on Scott Adams' Blog