People often say that a Capital Levy merely imagines everybody dying at
the same time. This parallel is wrong in degree when you are considering
the ease of paying duty or of changing the market values by a glut of
shares, and it is still more wrong when you are thinking of ease of
valuation. When a man is dead, he is dead, and in estimating the death
duty you have not to bother about how long he is going to live! But
every time you value a life interest and take a big slice of it for tax
you are probably doing a double injustice. The charge is incorrect for
two taxpayers. On a flat rate of tax this difficulty might be made less,
but the essence of any effective levy is a progressive scale. Moreover,
whether you are right or wrong about Robinson's tax, he has nothing in
hand with which to pay it. He has either to raise a mortgage on his
expectation (on which he pays _annual_ interest) or pay you by
instalments. So far as his burden is concerned, therefore, there is no
outright cut. You will be getting an annual figure over nearly the whole
class of life interests and reversions. It is difficult to see how one
can escape making adjustments year after year for some time in the light
of the ascertained facts, until the expiry of, say, nine or ten years
has reduced the disparities between the estimated valuations and the
facts of life to smaller proportions.

Next come those valuations which depend for their accuracy upon being
the true mid-point of probabilities. A given mine may last for five
years in the view of some experts, or it may go on for fifteen in the
view of others, and you may take a mid-point, say ten, and collect your
tax, but, shortly after, this valuation turns out to be badly wrong,
_though all your valuations in the aggregate are correct_. While the
active procedure of collecting the levy is in progress for a number of
years these assessments will simply shout at you for adjustment. There
are other types of difficulty in assessment which involve annual