Which ethical theory was developed first?

The correct answer is Act-Utilitarianism, as it was the first among the listed ethical theories to gain prominence during the Enlightenment in the 18th century. Act-Utilitarianism is based on the principle of utility, which was articulated by philosophers such as Jeremy Bentham. It evaluates the morality of individual actions based solely on the consequences they produce, particularly in terms of maximizing happiness or pleasure.

The development of ethical theories reflects distinct philosophical movements and historical contexts. While virtue ethics can be traced back to ancient philosophers like Aristotle, and deontological ethics was more systematically articulated by Immanuel Kant in the 18th century, Act-Utilitarianism represents one of the earliest formalized approaches to ethics that centers on the consequences of actions rather than on rules or character traits, which are emphasized in the other ethical theories mentioned.

Thus, understanding the chronological development of these theories helps clarify why Act-Utilitarianism is recognized as one of the foundational ethical theories in the study of ethics.