I am not working on the project during July, so the blog has been a bit silent for a while. However, I decided to post something less serious and hopefully more entertaining in the meantime.

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This is a physics joke I’ve heard somewhere; I’m putting it here as it alludes to the uncertainty principle discussed in this blog; it is often called the ‘Heisenberg uncertainty principle’, as Werner Heisenberg was the first one to introduce the idea in the early 20^{th} century.

Heisenberg, Schrödinger and Ohm are on a road trip. Heisenberg is driving and their speed is way above the speed limit when they’re stopped by police. The police says:

– Are you aware that you were driving at 140 kilometres an hour?

Heisenberg, being very annoyed and upset, responds:

– Thanks! Now I have no idea where I am!

The police finds the answer a bit weird and asks Heisenberg to open the trunk.

– Um, did you know you have a dead cat here? the police asks.

Schrödinger immediately jumps out of the car and shouts angrily:

– *Now* we know, you idiot!

The police decides to arrest all of them for speeding, killing a cat and offending the police. Ohm resists.

***

Since I’ve been also writing about logic, here’s the only logic joke I know.

Three logicians walk into a bar. The bartender asks: “Are all of you getting a beer?” The first logician looks at the other two and says: “I don’t know.” The second one also says: “I don’t know.” Immediately after hearing this, the third logician exclaims: “Yes!”

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Perhaps my favourite book as a child was Lewis Carroll’s *Alice’s Adventures in Wonderland*, whose humour is often based on playing with logic. Here’s one example from Chapter Seven, *A Mad Tea-Party*.

‘Then you should say what you mean,’ the March Hare went on.

‘I do,’ Alice hastily replied; ‘at least – at least I mean what I say – that’s the same thing, you know.’

‘Not the same thing a bit!’ said the Hatter. ‘You might just as well say that “I see what I eat” is the same thing as “I eat what I see”!’

‘You might just as well say,’ added the March Hare, ‘that “I like what I get” is the same thing as “I get what I like”!’

‘You might just as well say,’ added the Dormouse, who seemed to be talking in his sleep, ‘that “I breathe when I sleep” is the same thing as “I sleep when I breathe”!’

‘It *is* the same thing with you,’ said the Hatter – –

***

I will conclude with a classic Knight and Knave logic puzzle. (For much more see https://sites.google.com/site/newheiser/knightsandknaves.) The setup is the following; you are on an island populated by Knights, Knaves and Spies. Knights always tell the truth, Knaves always lie and Spies can either lie or tell the truth. Moreover, the inhabitants always hang out in groups of three, one Knave, one Knight and one Spy and their only pastime is to give you logic puzzles consisting of figuring out who they are. So, you meet the inhabitants A, B and C, and they say:

A: I am a Knight

B: I am a Knave

C: B is not a Knight

Which one is which?