Articles on Law, Science, and Engineering

A CLASSIFICATION SYSTEM FOR MACHINES[index]

The courts have not established criteria for classifying machines as to the necessary competence of the user. We propose that the critical parameters for such a classification may be grouped under the heading of indeterminacy. If indeterminacy is measured from 0 to 1, a completely understood machine with a limited number of fixed behaviors would have an indeterminacy index approaching 0. A machine with an unlimited repertoire of behaviors would have an indeterminacy index of 1.

The more indeterminate a machine, the more the designer must rely on the user to control the behavior of the machine. A lawnmower has a low indeterminacy because it has a limited purpose and well defined operational modes. Conversely, personal computers and airplanes are highly indeterminate.

The indeterminacy index must be coupled with a dangerousness index to properly predict legal liability. An unprogrammed personal computer is highly indeterminate, but its potential for injuring people is limited. An airplane is also indeterminate, but it has great potential for causing injury. Using the 0 to 1 scale for dangerousness, a computer might be 0.05 and an airplane 0.9.

The legal risk associated with the use of a machine by an incompetent user will be a function of the indeterminacy and the dangerousness of the machine. The function should describe a legal risk index that is greater than either the indeterminacy or dangerousness index and approaches unity as these indices approach unity. For example, the sum of the indeterminacy and dangerousness indices less their product is a function that fulfills these criteria. Applying this analysis to a lawnmower, we find that, while a lawnmower is dangerous, it is dangerous in a limited number of manageable ways. Through proper engineering a lawnmower can be made relatively safe for an inexperienced user. An airplane, which combines both high indeterminacy and high dangerousness, cannot be made safe for an incompetent user.

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