The ultimate goal of machine ethics, we believe, is to create a machine that itself follows an ideal ethical principle or set of principles; that is to say, it is guided by this principle or these principles in decisions it makes about possible courses of action it could take. We need to make a distinction between what James Moor has called an "implicit ethical agent" and an "explicit ethical agent" (Moor 2006). According to Moor, a machine that is an implicit ethical agent is one that has been programmed to behave ethically, or at least avoid unethical behavior, without an explicit representation of ethical principles. It is constrained in its behavior by its designer who is following ethical principles. A machine that is an explicit ethical agent, on the other hand, is able to calculate the best action in ethical dilemmas using ethical principles. It can "represent ethics explicitly and then operate effectively on the basis of this knowledge." Using Moor's terminology, most of those working on machine ethics would say that the ultimate goal is to create a machine that is an explicit ethical agent.
We are, here, primarily concerned with the ethical decision making itself, rather than how a machine would gather the information needed to make the decision and incorporate it into its general behavior. It is important to see this as a separate and considerable challenge. It is separate because having all the information and facility in the world won't, by itself, generate ethical behavior in a machine. One needs to turn to the branch of philosophy that is concerned with ethics for insight into what is considered to be ethically acceptable behavior. It is a considerable challenge because, even among experts, ethics has not been completely codified. It is a field that is still evolving. We shall argue that one of the advantages of working on machine ethics is that it might lead to breakthroughs in ethical theory, since machines are well-suited for testing the results of consistently following a particular ethical theory.
One other point should be made in introducing the subject of machine ethics. Ethics can be seen as both easy and hard. It appears easy because we all make ethical decisions on a daily basis. But that doesn't mean that we are all experts in ethics. It is a field that requires much study and experience. AI researchers must have respect for the expertise of ethicists just as ethicists must appreciate the expertise of AI researchers. Machine ethics is an inherently interdisciplinary field.
The Importance of Machine Ethics
Why is the field of machine ethics important? There are at least three reasons that can be given. First, there are ethical ramifications to what machines currently do and are projected to do in the future. To neglect this aspect of machine behavior could have serious repercussions. South Korea has recently mustered more than 30 companies and 1000 scientists to the end of putting "a robot in every home by 2010" (Onishi 2006). DARPA's grand challenge to have a vehicle drive itself across 132 miles of desert terrain has been met, and a new grand challenge is in the works that will have vehicles maneuvering in an urban setting. The United States Army's Future Combat Systems program is developing armed robotic vehicles that will support ground troops with "direct-fire" and antitank weapons. From family cars that drive themselves and machines that discharge our daily chores with little or no assistance from us, to fully autonomous robotic entities that will begin to challenge our notions of the very nature of intelligence, it is clear that machines such as these will be capable of causing harm to human beings unless this is prevented by adding an ethical component to them.
Second, it could be argued that humans' fear of the possibility of autonomous intelligent machines stems from their concern about whether these machines will behave ethically, so the future of AI may be at stake. …