When conversation becomes dull and familiar, when your evening at the bar seems just like any other, when the people sitting with you start to yawn just as you start to talk, it may just be time to try cracking open the impregnable vault of these philosophical paradoxes.

Nothing can give greater satisfaction in a social situation than initiating a conversation that captures the minds and imagination of the people within the group. Philosophy, long known for turning everyday assumptions on their heads, is always a good subject to start talking about, as it rarely offends and more often than not gets people thinking about things they would usually take for granted. However before you can start sweet talking paradoxes you first of all have to know some; a couple should do the trick, enough to sound knowledgeable but not so many that you begin to bore. If you don’t know any don’t fear, because here is a quick run down on some of the best bar room puzzles that are sure to make your friends seem foolish.

• Zeno’s paradox.

One of the best Greek paradoxes this offering from Zeno makes movement a philosophical impossibility. Yep, simply get your friends to place their hands on the table and then explain to them how they are now stuck there until the end of time. Movement, according to Zeno, is impossible for a number of very obvious reasons to do with infinite regression. The basic theory behind Zeno’s paradox is that before a object can move to another place it first has to move to a place half way between. Fine, that makes sense. If i want to fly from London to New York I have to cross the Atlantic, no problem. Zeno continues however, doggedly pursuing this idea to its nonsensical end point, and asserts that before reaching half way the object must first move half way to half way. Again in-arguably true; before reaching half way across the Atlantic I must first travel half way to the half way point. I’m sure you can see where this line of reasoning is going now. Movement is impossible because an infinite number of half way points, requiring an infinite amount of time, must be passed through before an object can reach its destination. obviously absurd, but flawlessly logical.

• Russell’s Paradox

Russell’s Paradox disrupts all that we know about the mathematical set theory first proposed by Georg Cantor. The paradox is of course easy to explain but impossibly difficult to resolve and hinges on the problem of what to do with the set of all sets that do contain themselves. It is brilliantly explained here and in this you tube video.

In the bar it is easy to set your friends the challenge of asking them where would the waiter all of the beers that could not be contained in a glass. t’s kind of the universal solvent of paradoxes, nothing can contain it, but if nothing can contain it then where exactly is it.

• The Necktie Paradox

This is definitely one for the neatly dressed gambler. In this paradox it appears that two outcomes appear to have the same odds of winning when the reality is that only outcome is likely. For this one find two friends who are wearing ties and use them as models. Each, it is assumed, has received their tie from their respective wife as a Christmas present. The value of the ties is unknown but over drinks they start arguing over whose wife has treated who to the cheaper necktie. A wager is agreed upon with the winner receiving as his prize the more expensive tie; such is their level of appreciation for a gift fondly given.

Anyhow, the two men readily agree to the wager based upon the following line of reasoning:

• There is an equal probability that I may win.
• If I lose, then I lose a $30 necktie; but if I win, then I win more than the $20 necktie that I received for Christmas.
• Therefore, although I may lose by having the most expensive tie, the wager is to my advantage.

After a few drinks your friends will be wagering themselves into a state of undress.

For more puzzles of this kind, and for a selection of zen koans that are equally fiendish, visit my website dedicated to logical puzzles of every kind.