January 16, 2020

Unscientific Evidence

Objectives

1) What makes for "unscientific" evidence?

2) What are some examples of "unscientific" evidence?

3) Objective:

  • identify unscientific evidence
  • explain why it is unscientific

Recap

Claims and Bases

claims: statements about what is true or valid


bases: evidence (and assumptions about valid evidence) that support those claims

Scientific Evidence:

Transparent procedures

Systematic use of evidence

Test claim against alternatives

Acknowledge uncertainty

Transparent procedures

Transparent procedures

Unscientific Evidence

Paraphrasing Tolstoi

All [instances of scientific evidence] is alike; each [instance of unscientific evidence] is [unscientific] in its own way.

Paraphrasing Tolstoi

Despite an infinite number of topics for research:

  • Scientific evidence shares similarities in how it adheres to the four attributes.
  • Unscientific evidence can fail to meet four criteria in many different ways.

Stop and think:

  1. What is the guest's argument (claim)?

  2. What is the primary evidence she offers to support it?

  3. How does this evidence fail to meet the attributes (of scientific evidence)?

Unscientific Evidence: Personal experience

Evidence that appeals to personal experience:

A claim based on one's own personal (nonsystematic) observation or one's own reaction to an observation

Examples

"No one I knew voted for ____, so they must have cheated to win."

Unscientific Evidence: Personal experience

Personal experience can be misleading:

  • We generalize too quickly from a small number of cases (acknowledge uncertainty)

  • Our exposure to the world may be skewed (systematic use of evidence)

  • We observe the world selectively (consider alternatives; systematic use of evidence)

Personal experience: Generalize too quickly

Claim

"I have a gluten intolerance".

Evidence

"I had [some product] a few times and each time I felt sick to my stomach afterwards."

Personal experience: Skewed Exposure

Claim

"Illegal immigrants are criminals."

Evidence

"In news stories I see, most of the criminals are illegal immigrants."

Selective Perception

Claim

"Large, public places like mass transit are more dangerous than driving."

Evidence

"Remember all those terrorist attacks or mass shootings in public places and public transit?"

Stop and think:

  1. What is his main argument (claim)?

  2. What is the primary evidence he offers to support it?

  3. How does this evidence fail to meet the four attributes (of science)?

What kind of claim is that?

Appeal to common sense

Evidence from common sense:

  • argue that a claim is true because it is something "everyone knows" or "just makes sense"

Unscientific Evidence: Common Sense

Problems with common sense

  • Often based on analogy emphasizing superficial similarities between very different situations (systematic use of evidence)

  • Often common sense reasons against the claim (consider alternatives)

False analogies

Claim:

In 2003:

"US military invasion in Iraq will bring peace, democracy, and economic growth to the country."

Evidence?:

"US invasion of Germany (1945) brough end to war, removal of Nazis, democracy, and a growing economy."

Opposite claims possible

Claim

Opposite claims possible

Counterclaim

Stop and think:

  1. What is Miller's main argument (claim)?

  2. What is the primary evidence he offers to support it?

  3. How does this evidence fail to meet the four attributes (of science)?

What kind of claim is that?

Appeal to authority


Arguing that claim is true because a person with authority says it is true.

Problems with authority

  1. Experts may be wrong/expertise irrelevant (Transparent Procedures)
  2. Experts may have an agenda (Transparent Procedures)
  3. We can "cherry pick" supportive experts (systematic use of evidence)
  4. Experts can disagree (acknowledge uncertainty)

Expertise wrong/irrelevant

Claim:

As far as the cyber, I agree to parts of what Secretary Clinton said. We should be better than anybody else, and perhaps we're not. I don't think anybody knows it was Russia that broke into the DNC. I mean, it could be Russia, but it could also be China. It could also be lots of other people. … So we have to get very, very tough on cyber and cyber warfare. It is — it is a huge problem. … The security aspect of cyber is very, very tough. And maybe it's hardly doable.

  • Donald Trump

Evidence:

I have a son. He's 10 years old. He has computers. He is so good with these computers, it's unbelievable.

Experts are motivated

Claim:

"You should take this brand-name statin, X, to reduce your cholesterol."

Evidence

"I am a doctor."

  • Undisclosed: I receive free meals from the manufacturer of drug X.

Cherry picking experts

Claim:

Removing restrictions on gun ownership stops crime.

Evidence

National Association of Chiefs of Police surveyed 20,000 sheriffs and chiefs of police, and found that vast majority agreed that "armed citizens help law enforcement reduce violent criminal activity".

  • This ignores police chiefs who publicly call for gun restrictions

Proliferating authorities

What do we do when some experts say one thing, and others say another?

  • Without features of scientific evidence, we can choose any expert we want.
  • Consider debates about climate change: people cite competing surveys of experts

Conclusion:

Conclusion:

  1. Many ways for claims to be unscientific
  2. Comes down to not meeting four attributes of scientific evidence
  3. You can recognize when this happens