It's impossible to add up all the indirect environmental costs of a windmill, but a good proxy for this arithmetic is simply to compare the resources consumed (in dollars) with the output produced (in dollar value of the electricity).

FORBES: Environmentalist, Spare That Tree

It is impossible for any one manager to significantly add value and it seems likely the vast number of managers will result in, at best, a market rate of return net of fees, with significantly greater investment and operational risk.

FORBES: Pensions Perilously Binging Upon Hedge Funds, Funds of Funds and Funds of Funds of Funds (March 20, 2007)

He will add that it was impossible to predict a year ago that the markets would be "stood on their head".

BBC: Warning on slow mortgage recovery

Until we have a precise diagnostic test for ADD, however, it will be impossible to give truly accurate figures.

NPR: Excerpt: 'Delivered from Distraction'

Under pooling rules, companies that are combining simply add their accounts together, making it impossible to discern the cost of the acquisition.

ECONOMIST: Draining the pool

It will then self-destruct not in flames, its inventors hasten to add, but because contact with the air eventually renders its surface opaque, making it impossible for the laser in a disc player to read the data beneath.

ECONOMIST: A new twist on an old polymer