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CHAPTER SUMMARY

When Claims Conflict

  • Many times we need to be able to evaluate an unsupported claim—a claim that isn’t backed by an argument. There are several critical thinking principles that can help us do this. An important one is: If a claim conflicts with other claims we have good reason to accept, we have good grounds for doubting it.
  • Sometimes there is a conflict between a claim and your background information. Background information is the large collection of very-well-supported beliefs that we rely on to inform our actions and choices. The relevant principle is: If a claim conflicts with our background information, we have good reason to doubt the claim.
  • It’s not reasonable to accept a claim if there is good reason to doubt it. In the case of claims that we can neither accept nor reject outright: We should proportion our belief to the evidence.

Experts and Evidence

  • An expert is someone who is more knowledgeable in a particular subject area than most others are. The important principle is: If a claim conflicts with expert opinion, we have good reason to doubt it.
  • We must couple this principle with another one: When the experts disagree about a claim, we have good reason to doubt it. When we rely on bogus expert opinion, we commit the fallacy known as the appeal to authority.

Personal Experience

  • Many claims are based on nothing more than personal experience, ours or someone else’s. We can trust our personal experience—to a point. The guiding principle is: It’s reasonable to accept the evidence provided by personal experience only if there’s no reason to doubt it.
  • Some common factors that can raise such doubts are impairment (stress, injury, distraction, emotional upset, and the like), expectation, and our limited abilities in judging probabilities.

Fooling Ourselves

  • Some of the common mistakes we make in evaluating claims are resisting contrary evidence, looking for confirming evidence, and preferring available evidence.
  • To counteract these tendencies, we need to take deliberate steps to examine critically even our most cherished claims, search for disconfirming evidence as well as confirming, and look beyond evidence that is merely the most striking or memorable.

Evaluating Sources: The Internet and Beyond

  • The news media, social media, the Internet, and the print world are loaded with unreliable sources, fake or false news, and deceptive or misleading claims everywhere.
  • The best way to avoid media nonsense is to read critically; size up authors, bloggers, and publishers; sort out claims; compare sources; uncover the source’s purpose; and check alternative sources.

Fake News

  • Fake news consists of bogus news stories that masquerade as truthful reporting. They deceive, mislead, and misinform. But there are ways to avoid these traps.
  • Some tips for spotting fake news: consider the source, read beyond the headline, ask what’s the support, and check your own biases.

Advertising and Persuasion

  • Advertising is another possible source of unsupported or misleading claims. We should realize that we generally have good reason to doubt advertising claims and to be wary of advertising’s persuasive powers.