But just as much as it is easy to find the differential [derivative] of a given quantity, so it is difficult to find the integral of a given differential. Moreover, sometimes we cannot say with certainty whether the integral of a given quantity can be found or not.
There is no doubt that the countries that now have a very large debt have not introduced the kind of structural reforms that Germany did and are therefore at a disadvantage. But the problem is that this disadvantage is becoming even more pronounced through the punitive policies in place.