Pub Life: Shaving the Zebra

A zebra.

Two barmen in matching polo shirts, one small, one tall, stand behind the bar with arms folded engaged in debate with a regular sat at the bar.

The tall bar­man leads: “No, you’re not get­ting what I’m say­ing: I’m ask­ing, does a stair­case go up or come down? Which way does it go?”

Up,” says the baf­fled reg­u­lar. “If it didn’t go up, you wouldn’t need it to come down. That it comes down is a side effect of it hav­ing gone up in the first place.”

No, it’s both. It goes up and comes down. It doesn’t mat­ter that it was built specif­i­cal­ly to go up. Once you’ve got an up, the stair­case has to go down as well. So it goes both ways.”

The small bar­man frowns, laughs qui­et­ly, and shakes his head.

What are you on about? What are you actu­al­ly on about?”

Alright, scratch that, here’s anoth­er one: is a zebra black with white stripes, or white with black stripes? Eh? Think about it.”

The reg­u­lar says, con­fi­dent­ly: “White with black stripes.”

Yeah, but how do you know for sure?”

Shave it.”

The small bar­man claps in delight.

He’s got you there, mate!”

Alright, what about this one: we’re all agreed stairs go up and down–”

Reg­u­lar: “No, but car­ry on.”

– but what about esca­la­tors? Does an esca­la­tor go up, or come down?”

You’ve hoist­ed your­self by your own petard here,” says the reg­u­lar. “It depends which way it’s going, doesn’t it? I mean, you lit­er­al­ly get one to go up, and anoth­er to come down.”

Ah, see, no, you’re wrong, and I’ll tell you why: because it has to come down on the under­side or it can’t go up. It’s a loop. So esca­la­tors always go up and down, just like stair­cas­es. Makes you think, doesn’t it?”

6 thoughts on “Pub Life: Shaving the Zebra”

  1. Well if you shave a zebra, they’re black, and they start off as black embryos which gain white stripes lat­er :
    https://www.newscientist.com/article/dn21453-zoologger-dont-bite-how-the-zebra-got-its-stripes/

    Although there’s var­i­ous the­o­ries about why they’re striped, and it’s prob­a­bly a sum of dif­fer­ent fac­tors, the main rea­son seems to be tied to tem­per­a­ture reg­u­la­tion :
    http://rsos.royalsocietypublishing.org/content/2/1/140452

      1. Oh I realise that, but any excuse to get devel­op­men­tal biol­o­gy into a con­ver­sa­tion…

  2. The zebra was the bit I found myself won­der­ing about. I’m just sur­prised that no-one won­dered about putting the zebra on the esca­la­tor, or claimed that it couldn’t go down stairs.

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