More specifically, perhaps - when pollution is regulated in
absolute language (thou shalt not emit more than X; thou shalt
not emit any Y at all; thou shalt use technology Z to control
thine emissions, whether or not Z is effective in thy case)
information is lost from the cost/benefit analysis.
It's hard to measure the costs of pollution, partly because
(if I understand correctly) of a political decision early in
the Industrial Revolution that progress is too important to be
hobbled by liability. Where people are suing for damages, the
plaintiffs themselves provide abundant information about the
costs of a given practice; but it's very hard to sue for damages
from pollution.
When the factory is liable for the external costs of pollution,
and has evidence on which to base an estimate of those costs,
it can rationally balance those costs with the costs of adopting
a less-polluting process.
In environmental policy, though, it's customary to scream
indignantly that *any* pollution is intolerable; in other
words, to insist (falsely) that the costs of pollution are
always infinite. Well, one infinity equals another, so it's
hard to see how such rhetoric can ever lead to improvement.
Anton Sherwood *\\* +1 415 267 0685 *\\* DASher@netcom.com