The scientific part of this site has examined time travel as a feasible mode of transportation through time. It has also shown that the most interesting direction for travel is back into the past. But suppose time travel were possible. Is it ever ethical to travel back in time to change events that had already occurred, only in order to benefit from them in the present? Similarly, time travel into the future poses complex ethical questions.

Ethics is present in our everyday life. It affects our decisions in life as well as our entering socio-economical, and political alliances. Some decisions are of a personal nature: Is it ethical to cheat on your significant other, or to steal confidential information from your competitor, to run a stoplight when no one is looking? Then, there are other ethical questions which transcend the personal sphere, such as killing in self-defense, having an abortion, committing suicide, making use of euthanasia, discriminating against others, and engaging in (or rejecting) animal rights, just to name a few. These choices are difficult to make, and their consequences follow us whenever we go, even through the waves of time.

Ethics is considered to be a normative science, meaning that it is concerned with the norms of human conduct. Since it depends on the system of values under discussion, there is no rigidly defined "right" and "wrong," which can be put in a mathematical equation. Historically, ethics needs to be analyzed in relation with the systems of moral theories or beliefs, which has generated it. A few examples will illustrate this.

Moral Theories

1. Utilitarianism: Jeremy Bentham created this moral theory in the early 19th century. It is a theory based on consequentiality, meaning that only the consequences of the action count in making moral judgments. He believed that all our actions are governed by pleasure and pain. Actions are deemed morally "right" when they bring more pleasure than pain to society. Factors that need to be included to measure the pleasure/pain factor are the certainty or uncertainty of the desired result occurring, the nearness or remoteness of the action in terms of how soon the people will feel its effect, the "fecundity" (or how much pleasure and pain will continue in the future), the "purity" (i.e. the greatest amount of pleasure which can be caused with the least amount of pain), and the "extent" (referring to the number of people affected). By giving a plus to each factor that would cause pleasure, and a minus to each factor that would cause pain, adepts of Utilitarianism could determine whether the action was morally right or wrong.

2. Natural Law: St. Thomas Aquinas first proposed this theory in the 13th century. Natural Law is tied into modern Catholic beliefs: while it examines the consequences of an action, it also provides a certain set of rules, which must be followed in every situation, regardless of the consequences. Natural Law is based on practical reason, which prescribes the rules for our actions in order for us to be happy. Aquinas claims that we have certain fundamental inclinations that we are prompted to satisfy, such as the preservation of our lives, having and educating children, seeking knowledge, and living in society with others. Every action must be morally good in itself, good in its circumstances, and done with morally good motive. If any only of these elements is not satisfied, the act is deemed morally wrong and evil. Thus, murder, suicide, euthanasia, adultery, rape, theft, deceit, and slavery are deemed wrong with absolutely no exceptions.

3. Pure Practical Reason: Immanuel Kant created this theory in the 18th century. This theory uses the ideology that consequences do not count at all in making moral judgments, but that reason alone decides what is moral and immoral. Actions are considered moral if they are based on the pure motive and desire to do one's duty.

1. Utilitarianism Example: One of the best examples of Utilitarianism is present in the film "12 Monkeys." Bruce Willis is sent back in time to stop a terrorist who spreads biological substances that wipe out a lot of humans and change the world for the worse. The leaders of the new world have weighted the pleasure vs. pain of their action, that is, sending Bruce Willis back in time. He'll have the pain of going back in time, doing the research and possibly getting killed, but if he succeeds, the pleasure -- no biological warfare -- would be much greater, and thus it seems ethical to send him back in time to change the past for benefits in the present.

2. Natural Law Example: The series "Quantum Leap" fits very often into this category. All actions of the character Sam fit the criteria of being morally good in themselves, good in their circumstances, and done with morally good motive. He neither kills anyone for a positive outcome, nor does anything morally wrong. Moreover, the circumstances are always good, and his motive is to make right what once went wrong.

3. Pure Practical Reason Example: In "Final Countdown," the crew of the ship has the capacity to shoot down the Japanese planes attacking Pearl Harbor, hence saving the lives of the people who live there. However, the crew is worried about the outcome of their interference and is not sure what is ethically correct to do because of the consequences of their actions. According to pure practical reasoning, it's their duty to protect the United States no matter what the consequences are, and therefore it would be ethically correct to get involved in the situation.