Two construction workers, Jack and Bob, are seated in a rough pub when a well dressed man enters, orders a beer and perches on a stool at the bar. The two builders start to speculate on what his occupation might be.
Jack: I reckon he's an accountant.
Bob: No way – he’s gotta be a stockbroker.
Jack: He ain't no stockbroker! No stockbroker would come in here.
The argument proceeds inconclusively for some time until the volume of beer gets the better of Jack and he weaves his way toward the Gents. On entering he spots the well dressed man standing at a urinal. Curiosity and several beers get the better of the builder.
Jack: ‘Scuse me ... I don’t mean no offence, but me and me mate were wondering what you do for a living?
Suit: No offence taken! I'm a Logical Scientist by profession.
Jack: Oh! And what's that then?
Suit: I find it best to explain by example. Do you happen to own a goldfish?
Jack: Errr… yeah, asamatterofact I do.
Suit: Well then, it's logical to assume that you keep it in either in a bowl or in a pond. Which is it?
Jack: It's in a pond.
Suit: Well then, one can reasonably postulate that you have a large garden, then?
Jack: Yep, I have got a big garden!
Suit: Well then, it's logical to assume that in this town if you have a large garden then you live in a large house?
Jack: I've got a five-bedroom house. Built it myself!
Suit: Well, given that you've built a five-bedroom house it is logical to assume that you haven't built it just for yourself but that you are quite likely married?
Jack: Yes, I am married. I live with my wife and three children.
Suit: Well then, would it be logical to assume that you are sexually active with your wife on a regular basis?
Jack: You bet! Four nights a week!
Suit: Well then, is it not logical to propose that you do not find it necessary to gratify yourself particularly often?
Jack: Me? Never!
Suit: Well then, there you are! That's logical science at work!
Jack: How's that then?
Suit: You see, simply by finding out that you had a goldfish, I've deduced intimate details of your sex life.
Jack: Wow! That's pretty impressive. Thanks, mate!
Both leave the Men’s Room and Jack returns to his mate.
Bob: I see the suit was in there. Didja ask him what he does?
Jack: Yep! He's a logical scientist!
Bob: What's that then?
Jack: I'll try and explain. Do you have a goldfish?
Jack: Well then, you're a wanker.