Natural Moral law is a deontological absolutist ethical theory developed by Thomas Aquinas that focuses on telos (purpose) and reaching eudaimonia. The idea of telos is central to natural moral law as aquinas believed that despite the absolutist and duty based approach to moral decision-making, we strive to act good because of the end goal of reaching ultimate happiness and satisfaction by God. This concept was initially introduced by Aristotle who heavily influenced Aquinas to which he adapted these beliefs by stating that a humans telos and purpose is the union with God. Aquinas formulated five primary precepts that he believed perfectly aligned with Christian faith and the importance of absolute rules. They are as follows: Worshipping God, Preservation of Life, Reproduction, Education of offspring, living in an ordered society. These precepts, Aquinas believed, were to be used as a moral framework to decide whether an action was moral or not. If an action went against one or more of the primary precepts then it was deemed immoral, and would not lead to the end goal of eudaimonia. Alongside the primary precepts Aquinas introduced secondary precepts, which posed as more specific rules than the generalised primary five. An example is, the primary precept of preservation of life, which can lead to the secondary precept “do not kill”. It is common however for an action, when graded against the primary precepts, to be contradictory in nature, where the commission of the action can go against a precept but the restraint of the action would also go against another precept. Aquinas responded to this controversy by introducing the doctrine of the double effect. This was a doctrine that adjusted the criteria for a moral action (on special circumstances) to the following; if an action has both a good and bad effect, then it is vital that the good effect is the intention and the bad effect is merely the side effect. The good effect must not be achieved by means of the bad effect and there must be a proportionate reason for allowing the bad effect. An example given is self defence. Although self defence can go against preservation of life (if the suspect is killed), your intention is to protect yourself and the death of the perpetrator is simply the negative side effect. Alongside the five primary precepts, Thomas Aquinas recognised four tiers of law; eternal law, divine law, natural moral law, and human law. Eternal being gods absolute law that is unchanging and universal. Divine law which revelation sent by god to explain gods eternal law. Natural law which is how humans have been able to perceive the divine law and human law which are the customs and practises of society. These four tiers reinforce the origin to moral guidance as being God ensuring that Natural Moral Law holds religious authority.