natural law

The telos/ultimate end

Aquinas thought moral acts were free acts aimed at achieving an immediate end, and also an ultimate end. Achieving an ultimate end brings ultimate happiness and satisfaction, a thing not found in this world (even love between a couple is tinged ultimately with the sadness of grief). We should pursue this ultimate happiness.

The four tiers of law

Aquinas advocated an approach to ethics based on a universal order that all moral rules were based on. Eternal law was the reason of God, known to human beings through revelation (divine law) and natural law (discoverable through the right use of reason). Human law was based on these sources (and if it wasn't, it need not be followed).

The key precept: the synderesis rule:

Natural law involves rationality The order of reason guides our action and must not be ignored. Reason directs us to do good and avoid evil, and all other principles flow from this reason.

Primary precepts and secondary precepts:

Aquinas thought that synderesis entailed certain primary precepts. Aquinas reflected on the purpose of human beings and concluded that synderesis entailed the need to protect life, reproduce, educate offspring, live in society and love God. Secondary precepts are rules that follow a primary precept -so, for example, it is right for a doctor to give medicine to a patient to save their life.

Real and apparent goods:

Humans do bad things because they are mistaken by apparent goods. Someone who steals a neighbour's new car, has made a mistake about the pleasure gained from acquiring a new care

The doctrine of double effect:

It is possible for some actions to have two effects, one which upholds a precept and another which does not. If the person intends the good effect, then they can be justified in acting in that way. So self-defence is right if I am doing it to preserve life, but not if I am doing it to kill someone. The other effect is foreseen but not intended.