Return to Blog Homepage

Flawctober: The Perception vs. Reality Fallacy

  • by Laura Santoski
  • Oct 17, 2018
  • LSAT


In preparation for the November 2018 LSAT, we’re going to spend the month of October going over some of the most common logical fallacies we see on the LSAT. Being able to reliably identify these fallacies will help you out on a ton of questions on the LSAT — about half the questions in Logical Reasoning section, in fact. Over this month, we’ll be doing such a thorough investigation into some of these common fallacies that we hereby dub this month Flawctober. Today, we’re discussing the perception vs. reality fallacy.

“Gwyneth Paltrow says that the best way to cure a cold is to drink a big mug of peppermint tea mixed with apple cider vinegar, so anyone beginning to feel cold symptoms should imbibe this mixture as a surefire way of making themselves feel better.”

“A newspaper conducted a survey of 100 football fans, 75% of whom said that football-related brain damage is not a serious concern for professional football players. One can thus conclude that NFL players have nothing to worry about when it comes to whether their sport of choice is harming their brains.”

“President Donald Trump’s uncle was a science professor, and Trump has noticed a lot of scientists on both sides of the climate change issue; therefore, the jury’s still out on whether climate change is really a thing.”

What do all of these arguments have in common (aside from being ridiculous, of course)? They’re all based on what someone believes to be the truth. We at Blueprint call this the “perception vs. reality” flaw.

What is the “perception vs. reality” fallacy?

As much as we’d like to believe we all know everything, when it comes to the LSAT, whoever you’re citing as support needs to be a reasonable authority on the conclusion you’re trying to draw.

The “perception vs. reality” fallacy occurs when the person or people cited in the premises can’t be reasonably expected to know about the conclusion that’s being drawn.

In other words, you could cite Cardi B’s opinion when drawing a conclusion about releasing diss tracks or wearing exceptional outfits or getting in fights with Nicki Minaj, but you can’t validly use her opinion to support a conclusion about, say, the conflict in the Middle East.

How can I identify when an argument contains this fallacy?

There are a couple common indicators that an argument contains a perception vs. reality fallacy:

• The premises are about what people think or believe, and the conclusion is phrased as being definite (for instance, in the Gwyneth Paltrow example above, you could validly draw a conclusion about what Gwyneth believes is the best cold remedy, but not a conclusion about what the most effective cold remedy is)

• The argument contains a study or survey, but it’s used to support a conclusion that the group being surveyed isn’t qualified to speak on (see the NFL example above – you can draw a conclusion about what fans perceive as problems for players, but not about whether brain damage is or is not a problem for players)

How would I strengthen or weaken an argument containing this fallacy?

This fallacy is effectively a problem with the strength of the support being provided, so if you want to strengthen an argument where the perception vs. reality flaw is occurring, you need to establish that the person or people cited as support actually know what they’re talking about. For instance, in the Trump example above, you could strengthen the argument by adding in the information that Trump himself holds a PhD in environmental science and has studied the climate change issue extensively. (Stop laughing! That’s what you’d need to make the argument make sense.) Conversely, if you want to weaken this type or argument, you need to make it seem even less likely that the person has any clue what they’re talking about.

Submit a Comment