William Kent, "Employee Was A Subtype Of Person", HPL-SAL-88-9, Hewlett-Packard Laboratories, Oct. 21, 1988. [2 pp]

Employee Was A Subtype Of Person

William Kent
Database Technology Department
Hewlett-Packard Laboratories
Palo Alto, California

October 1988


A modern parable of schema evolution.

Employee is a subtype of Person. Personnel and Equipment are disjoint. Hiring employees is a different activity from leasing equipment.


Robots can be rented to do various jobs.

The robots can learn and adapt. Individual robots have different skill levels based on their experience, and hence can command different rental rates.

Expert system technology is such that the expertise of various experts is not always compatible. An expert system might function adequately with the expertise of one expert or the expertise of another, but not with both. Hence the knowledge of one robot can't simply be dumped into another in order to maximize the skill levels of both. Although whole robots can be cloned, their experiences continue to differentiate them into distinctive sets of capabilities.

Repair and maintenance of robots is expensive. The net value of a robot is the difference between the rental it earns and the cost of its maintenance. Thus a separate account is maintained for each robot - in effect, each robot has its own bank account.

The more a robot can earn, the more it is worth keeping in good maintenance, and repairing when anything breaks down. High-income robots naturally get more discretionary maintenance such as painting and lubrication, earlier replacement of degrading parts, upgrading of components with state-of-the-art replacements, and so on. The robot with better skills earns more money and can afford better medical care and more luxuries.

Robots can be programmed, and learn, to choose their own discretionary maintenance activities, taking into account how much money they have. They decide how to spend their money.

Robots displace people from some jobs, creating more unemployment. The government decides to tax robot rental income to help finance the welfare programs. The rental agencies allocate these tax payments to the robot accounts, perhaps in proportion to their income levels. Robots pay income taxes.

Deteriorating capabilities of a robot can be refreshed by alternative activities that do not generate income, but provide balancing experiences that enhance their heuristic parameters and belief structures. Skill levels of robots, and hence their earning power, can be improved by game playing. The rental agencies pay other companies to provide such alternative activities and games for robots, again in proportion to the earning power of the robots. Wealthier robots can afford more relaxation and recreation.

Alternative activities include such things as chess tournaments. (Player was once a subtype of Person.) Prizes won by robots are credited to their accounts. After humans lodged protests of discrimination, the government decided to treat such winnings as taxable income for the robots.

Some robots contain programs allowing them to manage their accounts as investment funds. Some robots are specialists in this, providing advice and management services for the accounts of others, for a fee. (Robot has an intersection with Stockholder, and also with Client at a brokerage house. Stockbroker was also once a subtype of Person.)

Robots cloned from a highly skilled robot might require costly additional training to further specialize their skills. They might even incur maintenance or repair costs before they earn income. Expenses for such clones might be chargeable to the account of the master from which they were cloned. The accounts of several such robots might even be pooled, until the clones establish independent earning power. Wealth is shared within a family, one taking care of another; there might even be an inheritance concept.

Robots might learn from one another. They might assist one another, perhaps guiding them through situations in which they have little experience. They might be motivated to repair one another, and to protect each other from harmful situations.

Robots might exchange experiences with each other in their spare time, enhancing their own rule bases and heuristics in the course of such conversations.

When the mechanical parts wear out beyond justifiable repair, retired robots might still be useful as consultants to active robots, imparting the benefits of their accumulated experience and wisdom.

Employment agencies serve both people and robots. Sometimes humans and robots are available for the same type of work.

Some companies take robots on long-term lease, putting them on similar footing with human employees. Labor unions, seeing a real and present threat to the earning power of their members, have won the right to negotiate the labor rates at which robots are leased. Robots are registered as union members.

In personnel records, a human/robot field appears alongside the male/female field. Older versions of schemas are archived...

Employee was once a subtype of Person. Personnel and Equipment were once disjoint. Hiring employees was once a different activity from leasing equipment.

And so on. You can continue this story yourself in many ways, if you believe it.