It's back, that ancient debate about black money. With it come the same questions: How much are we talking about? Where exactly is it? How do we get it back? There are the usual messages doing the rounds on mobile phones, about how bringing back the loot will mean not having to pay taxes for decades. There are rumours of us being able to build fabulous roads, homes and universities with all that money.

Our MPs have, understandably, used the issue in much the same way a ping-pong player uses a ball, albeit with less finesse. Yesterday, for instance, there was a six-hour debate in the Lok Sabha followed by a rejection of LK Advani's adjournment motion on the UPA's alleged failure to act against tax evaders. Did the BJP act when it was in power? Advani didn't say.

A week ago, BJP MPs voluntarily gave a declaration in both houses that they did not have illegal wealth stashed abroad. The Congress promptly asked members of the NDA combine to declare that they had no illegal assets in India either.

What no one seems to agree upon is what that figure is. It varies, depending on who has a microphone thrust before him or her, from Rs 25 lakh crore to Rs 1,456 lakh crore. The massive discrepancy bothers no one, possibly because both figures are impossible to grasp in a country with a GDP -- according to the World Bank -- of approximately $1.73 trillion. Can a figure 10 to 20 times that really be stashed abroad illegally?

Even if it is, how do we separate it from the money earned legally? Most importantly, how do we prove it within a timeframe that makes sense for a country beset with other urgent issues that need to be resolved? No one's saying.