Two builders (Fred & Barney) are seated either side of a table in a rough pub when a well-dressed man enters, orders a beer and sits on a stool at the bar. The two builders start to speculate about the occupation of the "suit". Fred: "I reckon he's an accountant." Barney: "No way he's a stockbroker." Fred: "he ain't no stockbroker! A stockbroker wouldn't come in here!"

The argument continues itself for some time until the volume of beer consumed gets the better of Fred and he makes for the toilet. On entering the toilet he sees that the "suit" is standing at a urinal. Curiosity and several pints get the better of the builder...

Fred: "Scuse me.... no offence meant, but me and me mate were wondering what you do for a living?" Suit: "No offence taken! I'm a Doctor of Logical Science by profession." Fred: "Oh! What's that then?" Suit: "I'll try and explain by example.........Tell me, do you have a goldfish at home?" Fred: "Er...mmm...well yeah, I do as it happens." Suit: Well, it's logical for me to assume that you keep it in a bowl or in a pond. Which is it?" Fred: "It's in a pond!" Suit: "Well then it's reasonable for me to suppose that you have a reasonably large garden then?" Fred: "Well as it happens, yes I have got a big garden!" Suit: "Well then it's logical to assume that in this town that if you have a large garden that you have a large house?" Fred: "As it happens 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 and that you are quite probably married?" Fred: "Yes I am married, I live with my wife and three children!" Suit: "Well then it's logical to assume that you are sexually active with your wife on a regular basis?" Fred: "Yep! Four nights a week!" Suit: "Well then it's logical to suggest that you do not masturbate very often?" Fred: "Me? Never!" Suit: "Well there you are! That's logical science at work!" Fred:"How's that then?" Suit: "Well from finding out that you have a goldfish, I've told you about the size of garden you have, the size of house, your family and your sex life!" Fred: "I see! That's pretty impressive...thanks mate!" Both leave the toilet and Fred returns to his mate. Barney: "I see the suit was in there. Did you ask what he does?" Fred: "Yep! He's a logical scientist!" Barney: "What's that then?" Fred: "I'll try and explain. Let me see now.....Do you have a goldfish?" Barney: "Nope" Fred: "Well there you have it then, you're a wanker.