Consequentialism, which includes utilitarianism, stands in contrast to ethical systems that assert that morality is defined by a collection of ethical principles that are not unified (see Ethical Pluralism). The unifying principle of utilitarianism is the principle of Utility utility (see also Principles of Morals and Legislation#Chapter 1: The Principle of Utility). One advantage of moral systems that describe a unifying principle is that they provide a mechanism through which ethical conflicts might be resolved. For example, if two proposed actions are being considered (say building a bridge or using the same money to build an addition to a hospital), utilitarianism offers a theoretical basis for deciding which action is preferable. Estimated utility would constitute the decision criteria (although pragmatically the decision would be challenging). Other ethical systems, such as deontological ethics and virtue ethics, propose long lists of ethical principles, most of which lack a natural hierarchy or any other legitimate basis that would allow adherents to resolve conflicts.