logic

Argumentum ad Populam (Popular Appeal)

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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.

Equivocation

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An equivocation is a shift in meaning of a word. It can lead to invalid arguments and miscommunication. In this video, I discuss exactly how equivocation happens as a fallacy of reasoning and communication. I also give tips on how to spot an equivocation and how to respond to it.

NOTES

Further Reading

Aristotle identifies this fallacy in Sophistical Refutations

Begging the Question

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'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

 

Burden of Proof and the Problem of Evil

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In a recent video, I examined the Problem of Evil: How could a good God allow evil to exist? The argument is as follows:

  1. If God existed, He could prevent evil because He is all-powerful and all-knowing
  2. If God existed, He would prevent evil because He is all-good
  3. So, if God existed, evil would not exist
  4. But, evil exists
  5. So, God doesn’t exist

Theists typically object to premise (2) and in the video, I enumerated four reasons an all-good God could possibly allow evil. An interesting thing to note, however, is that I need not have done so in order to show the Problem of Evil fails because I didn’t have the ‘burden of proof.’

What is the ‘burden of proof’?

The ‘burden of proof’ is the obligation for proving why things are the way they are. In general, the burden of proof rests on whoever is making the claim. For example, let’s say Allen believes in aliens and Denise denies aliens exist (personally, I have no opinion on this matter). Denise says, “Aliens can’t exist: no one has ever seen one!” Allen points out, “That doesn’t prove anything. We’ve never seen dark matter, but that doesn’t mean it doesn’t exist.” Notice that Allen hasn’t proved that aliens exist, but he doesn’t need to. He only needs to show Denise hasn’t proven her claim.

Say Denise then gives Allen a reason. “Well, we should expect they would have made contact.” Notice, however, that this is yet another claim, so once again Denise shoulders the burden of proof, this time for the new claim (this will continue until Denise finds an acceptable claim to support the reasons she has given). So, Allen could ask, “Why believe aliens should have contacted us?” Again, Allen hasn’t proved we should not expect that aliens would have contacted us already. If he wants to make his point even stronger he can provide a reason why we shouldn’t. Maybe he could say, “An alien species might see that we don’t like outsiders.” This might be a good reason, in which case Allen’s point is all the more reinforced. However, if it isn’t, this doesn’t mean anything for Denise’s argument. She still has failed to make her case.

Who has the burden of proof in the Problem of Evil?

In the case of the Problem of Evil, the claim is being made: “God cannot exist because an all-good God wouldn’t allow evil.” For that reason, the burden of proof is on the atheist to show God could have no reason for allowing evil. After all, a being that is all-good would certainly not commit evil himself, but it is not obvious that he wouldn’t allow evil at all.

Let’s say the atheist gives us a reason: “When a person could prevent an evil but doesn’t we think that person is not good, so God would not be good if He were to allow evil.” Now we have a reason, but notice this reason is also subject to criticism. So, for example, we could point out that this isn’t always true. I might allow my son to procrastinate studying and fail a test in order for him to learn that there are consequences for irresponsibility. Or, more to the point, we might point out that God is an infinite intelligence, so He might have reasons for allowing evil that we don’t know.

Why give reasons?

Notice, however, that we still don’t need to give any reasons. It is sufficient to point out that the atheist’s argument doesn’t show God couldn’t allow evil. In fact, in this case it might be that it’s impossible to give the reasons God allows evil. First of all, it might be beyond our ken to understand. Human psychology hasn’t come far enough along to show us why we do everything we do, certainly we shouldn’t expect to understand why God does everything He does. If God were easy to understand, He wouldn’t be God. Second, God may have many reasons for allowing evil, and it may be that not every reason applies to every evil. So, for example, I might allow my son to surf a wave that scares him a little bit because it will develop courage in him. This is a different reason than why I let him fail the test. God might have an infinite number of reasons and expecting a silver bullet-type response is unrealistic. Finally, God might have some good purpose for hiding His reasons.

However, we might still give some possible reasons, as I do in the video, to make the case even more convincing. If these reasons fail, then nothing is lost. It has still been shown that the atheist has not provided sufficient justification for the claim that God couldn’t have any reasons for allowing evil.

Of course, ultimately the theist will not be satisfied with defending God against accusations of being an impossible being. She will want to go further and say God exists, and this is a claim that gives the theist the burden of proof for showing why we should believe this. The point here is that she need not prove this in the discussion of the Problem of Evil because here she doesn’t shoulder the burden of proof.

Should we kill off the weak?

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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.