Critical Thinking

A Skeptatic Dialogue, Part 3

Quentis and Firmatio: A Skeptatic Dialogue, Part 3

Continued from Part 2.


Firmatio: Right, so you don’t think you can fly anymore?

Quentis: Of course I still think I can fly, because I believe it is true.

Firmatio: That’s not a good reason.

Quentis: Sure it is. I have faith that I can fly. I know it in my heart. Besides, everyone in my family also believes it too. All those people can’t be wrong.

Firmatio: Yes they can, and just saying you believe something doesn’t make it true.

Quentis: My point exactly. Arguing from personal belief and appealing to popularity don’t make my idea true.

Firmatio: Are we done yet?

Quentis: Of course not. I still know that I can fly if I jump three times, and you still don’t believe me.

Firmatio: Okay then, prove it. Show me.

Quentis: So now you want evidence. Why don’t you just prove me wrong instead?

Firmatio: I can’t.

Quentis: Exactly, you can’t prove me wrong. It must be true.

Firmatio: No, you’re the one who said you could fly so you need to prove that you can.

Quentis: You’re saying that the burden of proof is on the person who makes the claim?

Firmatio: Yes.

Quentis: That’s a rather important point, isn’t it?

Firmatio: Why?

Quentis: The one who makes an extraordinary claim needs to provide the evidence that it is true. And as we talked about earlier, some kinds of evidence are better than others. The more extraordinary the claim, the more it goes against the things we already know to be true, the better the evidence we need to have. You need more than just my own story that I can fly to make you believe it, because my ability to fly would go against everything we know about and weak evidence isn’t enough to overturn all previous scientific knowledge.

Firmatio: Sure.

Quentis: Okay, but my grandmother won a nobel prize in physics.

Firmatio: What does that have to do with this?

Quentis: She is the one who told me about jumping three times and flying. She is an expert and she said it is true, therefore it is true.

Firmatio: But it’s not true.

Quentis: You don’t have a Nobel prize, you don’t have a PhD in physics, you’re not an expert. How can you know?

Firmatio: Maybe she’s wrong.

Quentis: She has a Nobel prize. She’s a leader in her field. She’s written dozens of books and hundreds of papers published in the best journals.

Firmatio: She’s still wrong. You can’t fly.

Quentis: Exactly. The argument from authority means that the fact that an expert says something doesn’t mean it’s true. Even a highly qualified person can be wrong. But that’s a different situation than a scientific consensus. If one expert claims something, that doesn’t make it true, but if 99% of the scientists in a field all agree on something, it probably is a good idea to believe it, at least until better evidence comes along.

Firmatio: But didn’t you already say that just because something is popular doesn’t mean it’s true?

Quentis: Yes, the fact that many people believe something isn’t enough make a conclusion, even if those people are supposedly experts. That’s why science bends to the evidence. Sometimes many experts are wrong, but we can only know this by looking at the evidence. If they are real scientists, they will change their minds based on what the evidence shows.

Firmatio: Fine, but you still haven’t proven you can fly like I asked you to.

Quentis: That’s because it only works when no one is watching me.

Firmatio: That’s ridiculous.

Quentis: No, it’s special pleading. I’m using ad-hoc reasoning to make up excuses for why I can’t prove what I believe. It doesn’t work around skeptics, but it does work if you believe in it. If you try it and it doesn’t work, it’s because you didn’t try hard enough. These are just convenient excuses in the face of no actual evidence.

Firmatio: So you’ll admit you’re wrong?

Quentis: No, I have one more reason why I know that people can jump three times and fly.

Firmatio: Fine, what is it?

Quentis: Ever since I started doing it, I’ve felt better. My joints don’t hurt as much and it is easier to do exercises. I know this is because I really am flying and it has a very real and positive effect on my life.

Firmatio: I don’t even know where to start with this one.

Quentis: You could start by admitting I’m right. You can’t deny the results.

Firmatio: You can’t fly.

Quentis: So you’re calling me a liar then? This has had an amazing positive effect on my life. I’m living proof! It works!

Firmatio: Maybe you believe it, but it’s still not true.

Quentis: So now you’re calling me crazy? I’ve never even suffered a headache, much less a psychiatric problem. You can ask my doctor, or my boss, or anyone else I know. They’ll tell you that I’m not a liar and I’m not crazy.

Firmatio: I never said you were crazy.

Quentis: You’re right. I jumped to a conclusion based on a false dichotomy. If what I believe is wrong, I must be either a liar or crazy. This assumes there are only two possibilities. However, I could just simply be wrong. I don’t have to be a liar, crazy, or stupid to believe something that isn’t true. I can just be wrong.


Continued in Part 4.

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Jay teaches English in Asia and loves skepticism and teaching above all else.

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