Tag Archives: Paradoxes

The Privacy Paradox of Rann Smorodinsky

rann  privacy

The following paradox was raised by Rann Smorodinsky:

Rann Smorodinsky’s Privacy Paradox

Suppose that you have the following one-time scenario. You want to buy a sandwich where the options are a roast beef sandwich or an avocado sandwich. Choosing the sandwich of your preference (say, the avocado sandwich) adds one to your utility, but having your private preference known to the seller,  reduces by one your utility. The prior people have on your preferences is fifty-fifty.

If you choose the avocado sandwich your utility is zero, hence you can improve on this by picking each type of sandwich at random with probability 1/2. In this case your private preference remains unknown and you gain in expectation 1/2 for having the sandwich you prefer with probability 1/2.

But given this strategy, you can still improve on it by choosing the avocado sandwich.

A Paradoxical Self-Referential Statement

A small discussion in a meeting about two decades ago.

Lior: Some people in the department think that they are wiser than what they really are

John: I am really wiser than what I think I am.

John’s statement is paradoxical (and funny). It looks similar to famous paradoxical self referential statements but it has some twist.

See also this question on philosophy stack-exchange