Expert Thoughts

Don’t Poison the Well: Questioning Someone’s Motives Exposes Your Weak Argument

If you hear someone challenging the motives of another, it might mean their argument is weak.
They're definitely calling out a few motives. (Wikimedia Commons)

They’re definitely calling out a few motives. (Wikimedia Commons)

“I never allow myself to have an opinion on anything that I don’t know the other side’s argument better than they do.” — Charlie Munger

One of the most common ways of refuting an argument is to call into question the motives of the other person. After all, this is easier than showing them what is wrong with the case they are making. Who has time for that, we’ve got meetings to attend.

It goes something like this. An investor, shorting the shares of a company lays out a thesis for why the company is a ponzi scheme. The company, upon hearing this, responds by challenging the motives of the investor saying something along the lines of “you just want the price to go down so you can make money.” This isn’t a fictional example.

William Ackman and Herbal Life are involved in just such a spat.

In a press release the company calls into questions the motives of Ackman: “(Ackman) has employed a sophisticated and unprecedented campaign to exert pressure on lawmakers and regulators to investigate and destroy Herbalife, all to protect the $1 billion bet he made against the company.”

It’s not about the merits of his argument, which they obviously disagree with but fail to refute, it’s about the billions of dollars he wants to protect.

“It’s perfectly possible,” writes Jamie Whyte in his clever book Crimes Against Logic, “to have some interest in expressing an opinion and for that opinion to be true.”

This is the motive fallacy also known as “poisoning the well” and it’s not just for refuting arguments but framing them as well.

We tend to think that if we expose the motives or special circumstances of the other person that we also refute their opinion. This isn’t the case. Why do we do this? Because it’s easy.

It’s easier than being confronted with a strong counter-argument or facts you’ve failed to consider. And it’s much easier than changing your mind. This fallacy effectively ends an argument by changing the subject to one of motives. And while it’s much more fun to speculate on the motives of others, it doesn’t get us any closer to the truth.

Politicians and journalists use this tool all the time. Sometimes it strikes as a weak rebuttal and sometimes its used to color people before they read the article.

New policies are often greeted with questions of motives, not debates on the effective merits of the policy. Tax-cut proposals become ‘pleasing the right,’ social programs become ‘appeasing the left.’

Nothing about the policy and its impacts becomes part of the popular discussion. Effectively, what we’re doing is poisoning the source so that nothing that comes from it can warrant serious consideration.

“An argument, unlike testimony,” writes Edward Damer in Attacking Faulty Reasoning, “is entirely separable from its source. For example, if an argument in opposition to the death penalty comes from a death-row inmate, the source would not make the argument any less worthy of our consideration.”

Perhaps this fallacy is too common and we’ve grown largely insensitive to it. Politicians are framed as doing things to please their base but that shouldn’t prevent us from giving consideration to the merits of what they are doing.

Another version of this is when journalists refer to politicians or think tanks alike as left or right. Without being explicit, that evokes a stance in us. “Those who lean the same way can then agree with its finding,” Whyte writes, “those who lean in some other direction can reject it.”

The reason this fallacy is so tempting is that it’s a lot of work to refute a view. And we’re busy. Too busy to do the work. That would require reading, investigating, and thinking. All things that seem to have fallen by the wayside in our sound-byte culture. Who has the time?

Instead we resort to unconscious mental trickery. We need to get through the day and we can’t do everything. So when someone backs us into a corner, it’s easier to come out and question their motives than to question our opinions.

The broader consequences of this fallacy can be seen in any newspaper, television debate, or even ourselves. When confronted with facts that contradict our world views, we often challenge the source and not the fact. In so doing, we twist reality to fit our thoughts rather than our thoughts to fit reality.

The next time you hear someone else challenging the motives of another, pay attention it might mean their argument is weak. And the next time you hear yourself challenging the motives of another, consider it a sign that your opinion is probably not as well-formed as you thought.

Shane Parrish feeds your brain at Farnam Street, a site that helps readers master the best of what other people have already figured out. Join over 40,000 other smart subscribers and sign up for brain food, his weekly digest of cross-disciplinary awesomeness.

Follow Shane Parrish via RSS.