Two blokes are sitting at a bar. While they're drinking, another man walks in and goes to the toilet. One of the blokes says to the other 'I haven't seen him in here before, but he looks quite rich. What do you think he does for a living? I reckon he's a lawyer.'  The other bloke replies 'no, he looks more like a doctor to me. I'll tell you what, I'll go in the toilet and ask him.

So, the bloke goes in the toilet, goes to the urinal next to the stranger and starts to pee.

'Sorry, but I haven't seen you in here before, and me and my mate were wondering what you do for a living.'

The stranger says,' Im a logical scientist.'

'What's that?'

'I'll give you an example. Do you have a goldfish?'

'Yeah'

'Do you keep it in a bowl or a pond?'

'A pond'

'Ok, so you've got a big garden then?'

'Yes'

'So, you've probably got a big house as well then, probably about 4 or 5 bedrroms?'

'Yep, 4 bedrooms'

'So you've got a wife and a couple of kids then?'

'Yeah, 3 kids'

'If you've got 3 kids, you get on well with your wife then? I mean, you have sex quite a lot?'

'Yeah, I'd say we have sex quite often'

'So, you probably don't masturbate then?'

'Not really, no' 

'So, from asking if you have a goldfish, I now know you have a big garden and house, 3 kids, you get on well with your wife, and you don't masurbate'

'Hey, that's pretty clever. Thanks very much'

The bloke goes back to his mate

'He's a logical scientist'

'What's that?'

'Well, I'll show you. Do you have a goldfish?'

'No'

'Well there you go then. You're a wanker'