Lewis Carroll was a devotee of logic games that explored the boundaries of sense and nonsense. This year's series of Daily Trojan ads features four of his well-known soriteses, which are polysyllogisms, or sequences of syllogisms that provide premises for unexpected conclusions. Depending on the premises, more than one conclusion is often possible.

 

Polysyllogism the Second

No birds, except ostriches, are 9 feet high.

There are no birds in this aviary that belong to any one but me.

No ostrich lives on mince-pies.

I have no birds less than 9 feet high.

One answer: No bird in this aviary lives on mince-pies.

 

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