"It is already a great and necessary proof of cleverness or insight to know what one should reasonably ask. For if the question is absurd in itself and demands unnecessary answers, then, besides the embarrassment of the one who proposes it, it also has the disadvantage of misleading the incautious listener into absurd answers, and presenting the ridiculous sight (as the ancients said) of one person milking a billy-goat while the other holds a sieve underneath