In a faraway galaxy, there is a space playground known as Cosmoland where children from various planets come to play together. One day, Astrid and Xander meet each other at the park.

Xander pulls a shiny black rock out of his backpack and proudly shows it to Astrid.

See if you can spot the fallacies in the conversation.

Xander

Hey Astrid! This rock is magical! It can grant wishes!

Astrid

Prove it, Xander.

Xander

Why don’t you prove that it’s not magical?

Astrid

You’re not fooling me. Anyway, forget about the rock. How about a bit of harmless fun? I’ve noticed that when someone talks inside that tunnel over there, the sound echoes to the area by the bushes. Bring a kid over there and tell him it’s a talking rock. I’ll hide in that tunnel and talk. It would be a hilarious joke.

Xander

That prank might seem harmless, but if we trick someone into thinking the rock is talking, we might start wanting to play tricks on our parents next. If we get good enough at that, we might start playing tricks on the space station crew members and pilots. If we confuse them enough, this whole space station might crash!

As Xander speaks, Astrid starts to feel dizzy.

Astrid

Xander, I’m getting a bout of space sickness. If I don’t take my pills, I might faint. Quickly grab them from my backpack.

Xander goes to Astrid's backpack, pulls out a bottle of pills, and starts examining them.

Xander

Hmm...these pills were made in a laboratory, so I don’t think you should take them. I’ve got some green tea in my backpack. How about I make you some of that instead?

Astrid

No, Xander. No research has ever shown that herbal tea cures space sickness.

Xander

I think we're both onto something here. I think the best choice for you is to take half a pill and half a cup of herbal tea.

Astrid

Half a pill is not enough. The recommended dosage for a child my age is one full pill.

Astrid takes a pill and immediately starts to feel better.

Astrid

Remember last week when we were here, we were trying to build a portal gun? Why don’t we head over to the engineering pod and give it another shot?

Xander

No way. Don’t you remember what happened last week? We realized there isn’t enough equipment to build a portal gun in Cosmoland’s engineering pod.

Astrid

But we spent four hours trying to build a portal gun last weekend. I’d feel like that time was wasted if we don’t give it another shot.

Xander

And even more time would be wasted if we try again. How about heading over to the gravity-free zone for a game of football, instead?

Astrid enthusiastically agrees and the two of them head over to the gravity-free zone to enjoy the rest of their afternoon in Cosmoland.

Chapters

Chapter 1: Circular Reasoning