It is much easier said than done.

The Mice once called a meeting to decide on a plan to free
themselves of their enemy, the Cat. At least they wished to find
some way of knowing when she was coming, so they might have
time to run away. Indeed, something had to be done, for they
lived in such constant fear of her claws that they hardly dared
stir from their dens by night or day.

Many plans were discussed, but none of them was thought good
enough. At last a very young Mouse got up and said:

“I have a plan that seems very simple, but I know it will be
successful. All we have to do is to hang a bell about the Cat's neck.
When we hear the bell ringing we will know immediately that
our enemy is coming.”

All the Mice were much surprised that they had not thought of
such a plan before. But in the midst of the rejoicing over their
good fortune, an old Mouse arose and said:

“I will say that the plan of the young Mouse is very good. But let
me ask one question: Who will bell the Cat?”

The Mice looked at one another and nobody spoke. Then the
old Mouse said:

“It is easy to propose impossible remedies.”