Testimony, Accusations, and the Ad Hominem Fallacy

Hello everyone.

I recently got into a discussion with someone who claimed I was being inconsistent in my application of the Ad Hominem fallacy.

Here's the situation. I found a passage from Atlas Shrugged by Ayn Rand. Now, I am only partially through the book and it's the first time I've read anything by her. So, I'm new to her philosophy and know nothing about her personal life. But I found this one quote quite insightful. So, I shared it on my Facebook page.

Someone responded that Ayn Rand was a terrible person and I should not be caught dead quoting anything from her.

I responded that I thought she was committing the error of Ad Hominem: instead of responding in a rational way to the quote, she was attacking the person.

Now, let's back up a little. Earlier, in a totally different discussion. I mentioned that since some of the accusers in a sexual misconduct accusation, were paid hundreds of thousands of dollars to give their testimony I think this fact taints their believability.

I was told by a third party that I had commitedd the exact same fallacy as the woman who hated Ayn Rand.

Did I?

I am thinking that this is like comparing apples to oranges. In the one case, we are not depending on witnesses to something that is said to have happened, but simply looking at a quote that you can agree with or disagree with based on rational assumptions or data you may have. In the other case, however, it seems that the integrity of the witness is indeed a factor in how much weight you should give to their testimony.

Am I wrong? Where is my thinking flawed?

To answer your initial question, I do not think these Ad Hominems are similar. If we didn't know why the witnesses were paid and we just assumed that they were lying because they were paid, this would be the Ad Hominem (Circumstantial) fallacy. The Ad Hominem with the quote would/might be the Ad Hominem (Guilt by Association) .

Now let's look at each more closely:

You shared a quote by Ayn Rand.
Someone said Ayn Rand was a terrible person and you should not quote her.

This is not a wholly unreasonable idea given that we don't like to make terrible people look good by reminding people of the good things they did or said. Of course, Ayn Rand is not Hitler, and I would guess that more people admire her (or are at least neutral to her) than not. So were they asking you not to quote her because they did not think you should give positive attention to a "terrible person" or did they disagree with the idea of the quote because they think Rand was a terrible person? The latter would constitute a fallacy, the former would not.

I mentioned that since some of the accusers in a sexual misconduct accusation, were paid hundreds of thousands of dollars to give their testimony I think this fact taints their believably.

This is a reasonable assumption and a good starting point - start by being skeptical of their sincerity/honesty based on what seems to be an excessive compensation. However, if you were to rule out they are NOT honest because of this, this would be the Ad Hominem (Circumstantial)  fallacy. If this is an issue that one cares about, they would be wise to investigate the circumstances around the payments. Is this common in high profile cases? How is the payment justified (if it is)? Are all of the witnesses really getting paid the amounts they are said to be getting paid? Is there collaborating evidence outside of testimony? The point is, skepticism is a good starting point, but rejection of the possibility based on that skepticism alone is fallacious.