• Skip to content

informal fallacies

Argumentum ad Verecundiam: Appeal to Illegitimate Authority

November 9, 2020 by The Philosurfer Leave a Comment

There are times in the pursuit of any knowledge--science, history, philosophy, etc.--when we have to rely on the testimony of others. What makes someone a reliable authority? In this video, I discuss the difference between legitimate and illegitimate appeals to authority.

NOTES

  • Appeal to authority- accepting the testimony of others as a grounds for belief or possibly knowledge
    • Types:
      • Eye-witness testimony
      • Opinions informed by experience
      • Expert research
  • What makes an authority legitimate?
    • Expertise
      • Conversant with all views on the topic
      • Vote of confidence from colleagues
      • Corroboration
    • Trustworthiness
      • Honest
      • Objective/unbiased
      • Sober-minded
      • Thorough
  • Argumentum ad Verecundiam- Appeal to an illegitimate authority
    • Types:
      • Not an expert in the subject
      • Not reliable
      • The person citing the authority is not reliable
    • Non-experts
      • Experts in other fields
      • Expertise too specified/general for the nature of the question
      • Not an expert at all
        • Internet sources
        • Celebrity appeal
      • Personal experience for general conclusions
    • Not trustworthy/reliable
      • Unreliably biased
      • Liars
    • Unreliable reporting
      • Misunderstanding the expert
      • Misquotation
      • Reporting bias
      • Unnamed experts

Further Reading

Filed Under: Material Fallacies Tagged With: ad verecundiam, appeal to authority, Borde-Guth-Vilenkin Theorem, celebrity appeal, existence of God, expert testimony, eye-witness testimony, history, illegitimate authority, informal fallacies, kalam cosmological argument, lawrence krauss, media bias, science, social media, william lane craig

Argumentum ad Populam (Popular Appeal)

October 27, 2020 by The Philosurfer Leave a Comment

The 'argumentum ad populum' fallacy assumes that probability of a belief is increased by the number of people that believe it. This video explores interesting examples of this, especially in democracy.

NOTES

  • argumentum ad populam- assuming that a lot of people believing something is a good reason to think it is more probably true
    • Arguments that this is fallacious reasoning
      • A1: psychological similarity
      • A2: gaslighting
      • A3: groupthink
      • A4: Mandela effect
  • argumentum contra populum- assuming that a lot of people believing something is a good reason to think it is less probably true

Further Reading

A pretty nice list of notes can be found here, though as you might be able to tell from the video I don't really agree with a lot of what is said there.

I also really liked this blog post, especially the discussion on Zeno and calculus (it was a little off topic--but, I mean, I made an entire career by being off topic)

My favorite logic book that deals with material fallacies is Peter Kreeft's Socratic Logic, and I like his discussion of the ad populum, though it's unfortunately short.

Filed Under: Material Fallacies Tagged With: ad populum, informal fallacies, logic, material fallacies, popular appeal

Ad hominem

May 4, 2020 by The Philosurfer Leave a Comment

An ad hominem fallacy is an attack on a person rather than their position or argument. Why is this fallacious? How can we identify this fallacy? How do we respond?

NOTES

  • ad hominem- attacking the person giving the argument rather than the argument itself
  • Three kinds:
    • circumstantial- attacking a person's circumstances
      • If they stand to gain from winning the argument, that's a reason to evaluate it, not reject it
    • abusive- attacking the person directly
      • Name calling
      • We can evaluate a person's character to see if they are trustworthy as an authority but not to evaluate their argument
    • tu quoque- attacking a person's hypocrisy
      • Hypocrisy doesn't automatically invalidate a person's position/argument, but a person can be a counterexample to their own position if they are living it out but not getting the predicted effect
  • Tips
    • How to identify: Would the response to the argument/position still make sense if we didn't know whose argument/position it was?
    • How to avoid it: Argue to understand others, not to win
    • How to respond to it:
      • Listen first
      • Ask the person to look past you and address the argument

Further Reading

Intellectuals, by Paul Johnson

Filed Under: Material Fallacies Tagged With: ad hominem, informal fallacies

Begging the Question

April 5, 2020 by The Philosurfer Leave a Comment

'Begging the question' (also 'petitio principii') is an informal fallacy of reasoning. In this video, I'll explain what it is, how it relates to circular reasoning, tips on avoiding it, and some common mistakes about it.

NOTES

Here's an example of "begs the question" used incorrectly in a DC Justice League comic by The Flash

Further Reading

Aristotle talks about this in Sophistical Refutations and in Prior Analytics book II.

Whatley's Elements of Logic is interesting for historical reasons, but there are much better logic books now. Read it for free online here. Don't buy it unless you like artifacts.

René Descartes' Meditations on First Philosophy for free here, or get a more recent translation here

 

Filed Under: Material Fallacies Tagged With: begging the question, begs the question, informal fallacies, logic, material fallacies

Should we kill off the weak?

July 25, 2019 by The Philosurfer Leave a Comment

This week we have been considering a view called ethical egoism and I gave you the example of the Plank of Carneades. When I give this dilemma in class, sometimes my students will argue for the egoistic choice by noting that in the moment of choice your survival instinct would kick in. You would naturally want to fight off the other person and giving up the plank would be unnatural. The implication is that things that are natural are good.

This style of argument is similar to what is given by a different but somewhat related system of morality. Evolutionary ethics is the view that we have a moral obligation to aid the evolution of our species. Natural selection hones the human race to be ever more adept at survival. To fight against this could only serve to weaken our race, and this is surely a bad thing. The human race naturally progresses towards a greater goal, so it would be wrong to interfere. However, living in a society instead of in nature creates an artificial environment in which evolution is stymied. Therefore, we should try to correct this as much as possible.

If this sounds at all familiar it should: this is the logic employed by the Nazis. Typically when someone compares something to Image result for nazi propagandathe Nazis, they do so fallaciously (a phenomenon documented here). In logic, a ‘false analogy’ is reasoning that just because two things are similar in one way, they must be similar in an unrelated way. This is exactly how much politicking goes on. I’ve heard people say (and I’m not endorsing anyone), “President Trump distrusts the press. You know who else had a problem with the press? Hitler.” A couple years back it was, “President Obama blames the rich for the problems in America. You know who else blamed a group of people? Hitler.”  The problem is that, just because someone is similar to Hitler in one way doesn’t mean they are similar to him in other, objectionable ways . Otherwise, we could say, “President Lincoln drank water. You know who else drank water?” However, in the case of evolutionary ethics, we are no longer appealing to irrelevant similarities. The Nazis reasoned that the weak would die off naturally but due to artificial circumstances (society) they survive. Worse, they are allowed to breed and thereby pollute the gene pool. The obvious conclusion is that they should not be allowed to survive. So, the Nazis euthanized them (for a gnarly example of what this would be like, watch season 2 of The Man in the High Castle, but not before reading the excellent book by my favorite author, Philip K. Dick.

Hopefully, you haven’t found the Nazi case too convincing because it is logically fallacious. Appeal to Nature is a fallacy on which we assume something is good just because it is natural (for our purposes, assume “natural” means “occurs without human engineering”). So, for example, in the movie “Friday,” Smokey says weed is from the Earth, implying it is good because it is natural. You know what else comes from the Earth? Lead. Does that mean you should shoot yourself (this isn’t a proof that marijuana is bad, but this argument certainly is)? When the evolutionary ethicist appeals to the “nature” part of natural Image result for drowningselection, she is making the same assumption. Even if evolution happens in nature, so does murder. That doesn’t make murder good.

The same should be said about the way my aforementioned students argued. They said that since we naturally have a survival instinct, we should employ that instinct. Again, just because something happens in nature, doesn’t mean it’s good. You may want to kill in order to survive, but that doesn’t mean you should. In fact, we have all kinds of natural desires we should avoid. We naturally desire to hit people, take things that aren’t ours, and eat the M&M’s out of the trail mix so dad is left with peanuts and salt-caked raisins. But we shouldn’t.

Filed Under: Ethics Tagged With: appeal to nature, egoism, ethical egoism, ethics, evolutionary ethics, hitler, informal fallacies, logic, natural, nature, nazis, philip k. dick, philosophy, survival