Two builders (Phil and Eric) 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.

Phil: - I reckon's an accountant.

Eric: - No way - he's a stockbroker.

Phil: - He ain't no stockbroker! A stockbroker wouldn't come in here!

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

Phil: - '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 Logical Scientist by profession.

Phil: - Oh! What's that then?

Suit: - I'll try to explain by example... Do you have a goldfish at
home?

Phil: - Er... Mmm . Well yeah, I do as it happens!

Suit: - Well, it's logical to follow that you keep it in a bowl or in a
pond. Which is it?

Phil: - It's in a pond!

Suit: - Well then it's reasonable to suppose that you have a large
garden

Phil: - As it happens, yes 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 have a large house?

Phil: - 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?

Phil: - Yes I am married, I live with my wife and three children.

Suit: - Well then it is logical to assume that you are sexually active
with your wife on a regular basis?

Phil:- Yep! Four nights a week!

Suit: - Well then it is logical to suggest that you do not masturbate
very often?

Phil: - Me? Never.

Suit: - Well there you are! That's logical science at work!

Phil: - How's that then?

Suit: - Well from finding out that you had a goldfish, I've told you
about your sex life!

Phil: - I see! That's pretty impressive...thanks mate!

Both leave the toilet and Phil returns to his mate.

Eric: - I see the suit was in there. Did you ask him what he does?

Phil: - Yep! He's a logical scientist!

Eric: - What's that then?

Phil: - I'll try and explain. Do you have a goldfish?

Eric: - Nope.

Phil: - Well then, you're a wanker...