By Terry Freedman.

In part 1 Lance Sharpe made the case for economic theory combined with intrusive technology to solve the driverless car problem: who to kill given two alternatives. Sharpe is wrong for several reasons.

His approach has a facade of objectivity. However, like all forms of cost-benefit analysis, the seemingly neutral figures conceal implicit biases. For example, being productive is defined, without saying so, as being in employment. Thus the 70 year old is deemed to be unproductive. This ignores the possibility that they may help others to be "productive", perhaps by looking after grandchildren while the parents are at work. It also denigrates the value of their experience and wisdom to zero.

Discounted Cash Flow is itself a flawed technique. It assumes the assistance of one rate of interest which remains constant over many years. It also rests on the assumption that a given amount of money is worth more now to an individual than the same amount in the future, even in the absence of inflation. This ignores the possibility that people may be willing to defer gratification.

Moreover, the god of rationality is invoked. Yet research, as well as lived experience, tells us that people do not necessarily act in a way that an economist would describe as rational, even if they are in possession of perfect knowledge.

Finally, the risk-taking areas of people's brains are not fully developed until their early 20s, according to research. Therefore whatever incentives or disincentives prevail, teens are likely to continue to behave in ways that make us oldies gasp with fright.

Tomorrow: an alternative analysis.