Possibly it serves to bring the notion into relief to state it in

algebraic terms.

And again I'm still reading from Learn at Hands Opinion.

If the probability be called P, the injury L and the burden B,

liability depends upon whether B is less than L multiplied by P.

That is, IE whether B is less than PL, unquote.

Hands reasoning has great power for all or

nothing precautions that completely eliminate the probability of loss.

But a more general version of the hand formula would think about the marginal

burden of precaution for example of tying down the barge with an additional cable.

And the marginal impact of that precaution in reducing the probability of loss.

Restated in marginal terms, the law should ask for

a potential defendants to take precaution, should call upon potential defendants to

take precaution up to the point at which the marginal benefit is equal to

the marginal reduction in probability times the loss.

Try to think, and now as homework, try to think of another legal rule or

regulation where the law should turn on a consideration

of marginal cost and marginal benefits.

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